Att G16_MDRO & CDI

MDRO and CDI Module

Multidrug-Resistant Organism & Clostridium difficile Infection
(MDRO/CDI) Module

Table of Contents

Background
Table 1: Core and Supplemental Reporting Choices for MDRO and CDI Module
Section I: Core Reporting
Option 1: Laboratory-Identified (LabID) Event Reporting
1A: MDRO LabID Event Reporting
1B: Clostridium difficile (C. difficile) LabID Event Reporting
Option 2: Infection Surveillance Reporting
2A: MDRO Infection Surveillance Reporting
2B: Clostridium difficile (C. difficile) Infection Surveillance Reporting
Section II: Supplemental Reporting
1. Prevention Process Measures Surveillance
a. Monitoring Adherence to Hand Hygiene
b. Monitoring Adherence to Gown and Gloves Use as Part of
Contact Precautions
c. Monitoring Adherence to Active Surveillance Testing
2. Active Surveillance Testing Outcome Measures
Table 2: Measures Delivered to CMS For Facilities Participating in Quality Reporting
Programs
Appendix 1: Guidance for Handling MDRO and CDI Module Infection Surveillance
and LabID Event Reporting When Also Following Other NHSN Modules
Appendix 2: Determining Patients Days for Summary Data Collection: Observation vs.
Inpatients
Appendix 3: Differentiating Between LabID Event and Infection Surveillance

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Background: Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant
Enterococcus spp. (VRE), and certain gram-negative bacilli have increased in prevalence in
U.S. hospitals over the last three decades, and have important implications for patient safety. A
primary reason for concern about these multidrug-resistant organisms (MDROs) is that options
for treating patients with these infections are often extremely limited, and MDRO infections are
associated with increased lengths of stay, costs, and mortality. Many of these traits have also
been observed for Clostridium difficile infection (CDI). The Healthcare Infection Control
Practices Advisory Committee (HICPAC) has approved guidelines for the control of MDROs.1
These guidelines are available at: http://www.cdc.gov/hicpac/mdro/mdro_toc.html). The
MDRO and CDI module of the NHSN can provide a tool to assist facilities in meeting some of
the criteria outlined in the guidelines. In addition, many of the metrics used in this module are
consistent with “Recommendations for Metrics for Multidrug-Resistant Organisms in
Healthcare Settings: SHEA/HICPAC Position Paper.”2
Clostridium difficile (C. difficile) is responsible for a spectrum of C. difficile infections (CDI),
including uncomplicated diarrhea, pseudomembranous colitis, and toxic megacolon, which can,
in some instances, lead to sepsis and even death. Although CDI represents a subset of
gastroenteritis and gastrointestinal tract infections in the current CDC definitions for HAIs,
specific standard definitions for CDI 3 should be incorporated to obtain a more complete
understanding of how C. difficile is being transmitted in a healthcare facility.
As outlined in the HICPAC guideline1, these MDRO and C. difficile pathogens may require
specialized monitoring to evaluate if intensified infection control efforts are required to reduce
the occurrence of these organisms and related infections. The goal of this module is to provide
a mechanism for facilities to report and analyze these data that will inform infection prevention
professionals of the impact of targeted prevention efforts.
This module contains two reporting options for MDRO and C. difficile, one focused on
Laboratory-identified (LabID) Events reporting and the second on Infection Surveillance
reporting. Reporting options are summarized in Table 1. Participants may choose either one or
both of the two core reporting options and then may also choose to participate in any of the
supplemental monitoring methods described in Table 1.
Note: LabID Event reporting and Infection Surveillance reporting are two separate and
independent reporting options. See Appendix 3: Differentiating Between LabID Event and
Infection Surveillance for key differences between the two options.

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Table 1. Core and Supplemental Reporting Choices for MDRO and CDI Module

Reporting Choices

MRSA or
MRSA/MSSA

Core
Method
Proxy Infection
Measures
A, B, C, D
LabID Event
Choose ≥1 organism
AND/OR
Infection
Surveillance
A, B
Choose ≥1 organism
Supplemental
Method
Prevention Process
Measures
Options:
 Hand Hygiene
B
Adherence
 Gown and
Gloves Use
B
Adherence
 Active
Surveillance
Testing (AST)
B
Adherence
AST Outcome
Measures
 Incident and
B
Prevalent Cases
using AST
N/A – not available or contraindicated

MDRO
CephR-Klebsiella, CRE
(E. coli, Enterobacter,
VRE
Klebsiella),
Acinetobacter spp. (MDR)
Method
Method

CDI
C. difficile
Method
±A,

A, B, C, D

A, B, C, D

A, B

A, B

Method

Method

Method

B

B

B

B

B

B

B

N/A

N/A

B

N/A

N/A

±No

B, C

±A,

B

surveillance for CDI will be performed in Neonatal Intensive Care Units (NICU),
Specialty Care Nurseries (SCN), babies in LDRP (Labor, Delivery, Recovery, and Postpartum), well-baby nurseries, or well-baby clinics. And, if conducting facility-wide monitoring
(Method C) the denominator counts (admissions, patient-days, encounters) for these locations
must be removed.

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Reporting Method (must choose to monitor by LabID Event or Infection Surveillance reporting
before supplemental methods can also be used for monitoring):
A:

B:

C:

D:

Facility-wide by location. Report for each location separately and cover all locations in
a facility. This reporting method requires the most effort, but provides the most detail
for local and national statistical data.
Selected locations within the facility (1 or more). Report separately for one or more
specific locations within a facility. This includes reporting individual Events and
denominator data for each of the selected locations. This reporting method is ideal for
use during targeted prevention programs. Note: MDRO “blood specimens only” is the
sole MDRO LabID event option for IRF, ED and 24-hour Observation locations.
Overall facility-wide. Report individual LabID events from each inpatient location and
aggregate denominator counts for the entire facility. Options include: (1) Overall
Facility-wide Inpatient (FacWideIN) to cover all inpatient locations. When using
FacWideIN reporting, facilities must also include location specific reporting for
outpatient emergency department (i.e., adult and pediatric) and 24-hour observation
location(s). NOTE: When following FacWideIN, facilities will be required to enter
denominators for all inpatient locations physically located in the hospital, as well as
denominators for all inpatient locations minus any inpatient rehabilitation facility (IRF)
and inpatient psychiatric facility (IPF) locations with separate CCNs. Totals reported
should not include facilities affiliated with the hospital that are enrolled separately.
Additionally, separate denominator data will be required to capture encounters for each
mapped emergency department and 24-hour observation location. (2) Overall Facilitywide Outpatient (FacWideOUT) to cover all outpatient locations affiliated with the
facility. Facilities may choose to monitor both FacWideIN and FacWideOUT.
Overall facility-wide: Blood Specimens Only. This method is available for MDRO
LabID Events only and targets the most invasive events. Report individual LabID
events from each inpatient location and aggregate denominator counts for the entire
facility. Options include: (1) Overall Facility-wide Inpatient (FacWideIN) to cover all
inpatient locations. Using this option, facilities must also include location specific
reporting for outpatient emergency department (i.e., adult and pediatric) and 24-hour
observation location(s). NOTE: When following FacWideIN, facilities will be required
to enter denominators for all inpatient locations physically located in the hospital, as
well as denominators for all inpatient locations minus any inpatient rehabilitation
facility (IRF) and inpatient psychiatric facility (IPF) locations with separate CCNs.
Totals reported should not include facilities affiliated with the hospital that are enrolled
separately. Additionally, separate denominator data will be required to capture
encounters for each mapped emergency department and 24-hour observation location.
(2) Overall Facility-wide Outpatient (FacWideOUT) to cover all outpatient locations
affiliated with the facility. Facilities may choose to monitor both FacWideIN and
FacWideOUT.

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I. Core Reporting
Option 1: Laboratory-Identified (LabID) Event Reporting
Introduction: LabID Event reporting option allows laboratory testing data to be used without
clinical evaluation of the patient, and therefore is a much less labor-intensive method to track
MDROs and C. difficile. These provide proxy infection measures of MDRO and/or C. difficile
healthcare acquisition, exposure burden, and infection burden based almost exclusively on
laboratory data and limited admission date data, including patient care location. LabID Event
reporting is ONLY for collecting and tracking positive laboratory results (e.g., cultures) that are
collected for “clinical” purposes (i.e., for diagnosis and treatment). This means that the results
of laboratory specimens collected for active surveillance testing (AST) purposes only should
not be reported as LabID Events.
LabID Events can be monitored at the overall facility-wide level for inpatient areas
(FacWideIN), and/or at the overall facility-wide level for outpatient areas (FacWideOUT). At
the overall FacWide levels and for IRF, ED, and 24-hour observation, MDROs can be
monitored for all specimen types or for blood specimens only. LabID Events can also be
monitored for specific locations with unique denominator data required from each of the
specific locations (i.e., facility-wide locations monitored separately [Method A] allowing for
both facility-wide and location-specific data, or by selected locations only [Method B]). If a
facility chooses to conduct FacWideIN surveillance for LabID Events, the facility must also
follow location-specific surveillance for that same organism in each outpatient emergency
department (pediatric and adult) and 24-hour observation location.
Laboratory and admission data can be used to calculate a variety of distinct proxy measures
including: admission prevalence rate and overall patient prevalence rate (measures of exposure
burden), MDRO bloodstream infection incidence rate (measure of infection burden and
healthcare acquisition), overall MDRO infection/colonization incidence rate (measure of
healthcare acquisition), and CDI incidence rate (measure of infection burden and healthcare
acquisition).
Use NHSN forms to collect all required data, using the definitions of each data field as
indicated in the Tables of Instructions. When denominator data are available from electronic
databases, these sources may be used as long as the counts are not substantially different (+ or –
5%) from manually collected counts.

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A. MDRO LabID Event Reporting
Methodology: Facilities may choose to monitor one or more of the following MDROs: MRSA,
MRSA and MSSA, VRE, CephR- Klebsiella, CRE, and/or multidrug-resistant Acinetobacter
spp. (see definitions below). For S. aureus, both the resistant (MRSA) and the susceptible
(MSSA) phenotypes can be tracked to provide concurrent measures of the susceptible
pathogens as a comparison to those of the resistant pathogens in a setting of active MRSA
prevention efforts.
Note: No Active Surveillance Culture/Testing (ASC/AST) results are to be included in this
reporting of individual results (See General Key Terms chapter). Do NOT enter surveillance
nasal swabs or other surveillance cultures as reports of LabID Events. AST tracking should be
recorded under Process & Outcome Measures.
MDRO Definitions: MDROs included in this module are defined below.
MRSA: Includes S. aureus cultured from any specimen that tests oxacillin-resistant, cefoxitinresistant, or methicillin-resistant by standard susceptibility testing methods, or by a laboratory
test that is FDA-approved for MRSA detection from isolated colonies; these methods may also
include a positive result by any FDA-approved test for MRSA detection from specific sources.
MSSA: S. aureus cultured from any specimen testing intermediate or susceptible to oxacillin,
cefoxitin, or methicillin by standard susceptibility testing methods, or by a negative result from
a test that is FDA-approved for MRSA detection from isolated colonies; these methods may
also include a positive result from any FDA-approved test for MSSA detection from specific
specimen sources.
VRE: Enterococcus faecalis, Enterococcus faecium, or Enterococcus species unspecified
(only those not identified to the species level) that is resistant to vancomycin, by standard
susceptibility testing methods or by results from any FDA-approved test for VRE detection
from specific specimen sources.
CephR-Klebsiella: Klebsiella oxytoca or Klebsiella pneumoniae testing non-susceptible (i.e.,
resistant or intermediate) to ceftazidime, cefotaxime, ceftriaxone, or cefepime.
CRE: Any Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, or Enterobacter spp.
testing resistant to imipenem, meropenem, doripenem, or ertapenem by standard susceptibility
testing methods (i.e., minimum inhibitory concentrations of ≥4 mcg/mL for doripenem,
imipenem and meropenem or ≥2 mcg/mL for ertapenem) OR by production of a
carbapenemase (i.e., KPC, NDM, VIM, IMP, OXA-48) demonstrated using a recognized test
(e.g., polymerase chain reaction, metallo-β-lactamase test, modified-Hodge test, Carba-NP).
Note: For in-plan CRE surveillance, facilities must conduct surveillance for all three organisms
CRE-E. coli, CRE-Enterobacter, and CRE-Klebsiella (Klebsiella oxytoca and Klebsiella
pneumoniae).
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MDR-Acinetobacter: Any Acinetobacter spp. testing non-susceptible (i.e., resistant or
intermediate) to at least one agent in at least 3 antimicrobial classes of the following 6
antimicrobial classes:
β-lactam/β-lactam
β-lactamase inhibitor
combination
Piperacillin
Piperacillin/tazobactam

Aminoglycosides

Carbapenems

Fluoroquinolones

Amikacin
Gentamicin
Tobramycin

Imipenem
Meropenem
Doripenem

Ciprofloxacin
Levofloxacin

Cephalosporins
Cefepime
Ceftazidime

Sulbactam
Ampicillin/sulbactam

Settings: MDRO LabID Event reporting can occur in any location: inpatient or outpatient.
Requirements: Facilities choose at least one of the reporting methods listed below and report
data accordingly:
Method
Facility-wide by location
Note: Must monitor All
Specimen sources

Numerator Data
Reporting

Denominator Data Reporting

Enter each MDRO LabID
Event from all locations
separately

Report separate denominators for each
location in the facility as specified in
the NHSN Monthly Reporting Plan

Enter each MDRO LabID
Event from selected
locations separately

Report separate denominators for each
location monitored as specified in the
NHSN Monthly Reporting Plan

Enter each MDRO LabID
Specimen Event from all
inpatient locations AND
separately for outpatient
emergency department, and
24-hour observation
location(s).

Report aggregate denominator data for
all inpatient locations physically located
in the hospital (e.g., total number of
admissions and total number of patient
days), as well as denominators for all
inpatient locations minus inpatient
rehabilitation facility and inpatient
psychiatric facility locations with
separate CCNs. Separate denominators
should be entered to capture encounters
for each mapped outpatient emergency
department and 24-hour observation
location.

Selected locations
Note: Must monitor All
Specimen sources with the
exception of IRF units, 24hour observation, and
emergency department

Overall Facility-wide
Inpatient (FacWideIN), All
Specimens

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Overall Facility-wide
Outpatient (FacWideOUT),
All Specimen sources

Overall Facility-wide
Inpatient (FacWideIN), Blood
Specimens Only

Overall Facility-wide
Outpatient (FacWideOUT),
Blood Specimens Only

Enter each MDRO LabID
Event from all affiliated
outpatient locations
separately.

Enter each MDRO LabID
Blood Specimen Event from
all inpatient locations AND
separately for outpatient
emergency department, and
24-hour observation
location(s).

Enter each MDRO LabID
Blood Specimen Event from
all affiliated outpatient
locations separately

Report only one denominator for all
outpatient locations (e.g., total number
of encounters, including ED and OBS
encounters in addition to other
outpatient locations.)
Report aggregate denominator data for
all inpatient locations physically located
in the hospital (e.g., total number of
admissions and total number of patient
days), as well as denominators for all
locations minus inpatient rehabilitation
facility and inpatient psychiatric facility
locations with separate CCNs. Separate
denominators should be entered to
capture encounters for each mapped
outpatient emergency department and
24-hour observation location.
Report only one denominator for all
outpatient locations (e.g., total number
of encounters).

Note: Facilities must indicate each reporting choice chosen for the calendar month on the
Patient Safety Monthly Reporting Plan (CDC 57.106).
For each MDRO being monitored, all MDRO test results are evaluated using either the
algorithm in Figure 1 (All Specimens) or Figure 2 (Blood Specimens only) to determine
reportable LabID events for each calendar month, for each facility location as determined by
the reporting method chosen. If monitoring all specimens, all first MDRO isolates
(chronologically) per patient, per month, per location are reported as a LabID event regardless
of specimen source [EXCLUDES tests related to active surveillance testing] (Figure 1); if a
duplicate MDRO isolate is from blood, or if monitoring blood specimens only, it is reported as
a LabID event only if it represents a unique blood source [i.e., no prior isolation of the MDRO
in blood from the same patient and location in ≤2 weeks, even across calendar months] (Figures
1 & 2). As a general rule, at a maximum, there should be no more than 3 blood isolates
reported, which would be very rare. If monitoring all specimens and a blood isolate is entered
as the first specimen of the month, then no non-blood specimens can be entered that month for
that patient and location. Report each LabID Event individually on a separate form.

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Definitions:
MDRO Isolate: Any specimen, obtained for clinical decision making, testing positive for an
MDRO (as defined above). Note: Excludes tests related to active surveillance testing.
Duplicate MDRO Isolate: If monitoring all specimens, any MDRO isolate from the same
patient and location after an initial isolation of the specific MDRO during a calendar month,
regardless of specimen source, except unique blood source (Figure 1).
EXAMPLE: On January 2, a newly admitted ICU patient has a positive MRSA urine
culture. The following week, while still in the ICU, the same patient has MRSA
cultured from an infected decubitus ulcer. The MRSA wound culture is considered a
duplicate MDRO isolate, since it is the second non-blood MRSA isolate collected from
the same patient and location during the same calendar month.
Unique Blood Source: A MDRO isolate from blood in a patient with no prior positive blood
culture for the same MDRO and location in ≤2 weeks, even across calendar months and
different facility admissions (Figure 2). There should be 14 days with no positive blood culture
result for the patient, MDRO, and location before another Blood LabID Event is entered into
NHSN for the patient, MDRO, and location. Additionally, if following all specimens, the first
MDRO for the patient, month, and location should be reported. Note: The date of specimen
collection is considered Day 1. NHSN recommends facilities keep an internal line listing log of
all positive isolates for reference in LabID event reporting.
EXAMPLE: (For blood specimens only reporting): On January 1, an ICU patient has a
positive MRSA blood culture which is entered into NHSN. On January 4, while in the
same location (ICU), the same patient has another positive MRSA blood culture which
is not entered into NHSN because it has not been 14 days since the original positive
MRSA blood culture while in the same location. On January 16, while in the same
location (ICU), the same patient has another positive MRSA blood culture. While it has
been more than 14 days since the initial positive MRSA blood culture from the same
patient and location was entered into NHSN (January 1), it has not been >14 days since
the patient’s most recent positive MRSA blood culture (January 4) while in the same
location. Therefore, the positive blood culture for January 16 is not entered into NHSN.
On February 1, the patient has another positive MRSA blood culture while in the same
location (ICU). Since it has been >14 days since the patient’s most recent positive
culture (January 16) while in the same location, this event is entered into NHSN.
EXAMPLE :( For all specimens reporting): For the same scenario as above, report the
January 1 positive MRSA blood culture and do not report any additional January events.
Additionally, report February 1 positive MRSA blood culture as this represents the first
MDRO for the patient, month and location.

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Laboratory-Identified (LabID) Event: All non-duplicate MDRO isolates from any specimen
source and unique blood source MDRO isolates. [EXCLUDES tests related to active
surveillance testing]. Even if reporting at the FacWide level, all reporting must follow rules by
location for reporting.
Notes:






A LabID Event calculator is available on the NHSN website to help with data entry
decision making around the 14-day rule.
If a facility is participating in FacWideIN surveillance and reporting, the facility
must also conduct separate location-specific surveillance in all outpatient
emergency department and 24-hour observation locations. This means LabID
Events for the same organism and LabID Event type (i.e., all specimens or blood
specimens only) must be reported from these locations even if the patient is not
subsequently admitted to an inpatient location during the same encounter.
All emergency department and 24-hour observation locations must be identified and
mapped as outpatient locations within NHSN. For more information about mapping
locations, see Locations chapter in the NHSN manual.

EXAMPLE: If monitoring blood specimens for FacWideIN (which requires
surveillance in the emergency department and 24-hour observation locations), a patient
has a positive MRSA laboratory isolate while in the emergency department. This
specimen represents an MRSA LabID Event and should be entered for the outpatient
emergency department. The next calendar day, the same patient is admitted to ICU and
three days later, has a second positive MRSA blood specimen. This specimen also
represents a unique LabID Event, because it is the first positive blood specimen in this
location (ICU). Note that while this patient has two LabID Events, the second specimen
that was taken from the ICU will be removed from most analysis reports.
EXAMPLE: If monitoring all specimens, on January 2, a newly admitted ICU patient
with no previous positive laboratory isolates during this admission has a positive MRSA
urine culture. This specimen represents a LabID Event since it is the first MRSA isolate
for the patient, the location, and the calendar month.
EXAMPLE: If monitoring all specimens for FacWideIN surveillance, on January 2, a
VRE wound culture is collected from the facility’s own ED. The patient is then
admitted to 4W the next calendar day. The ED culture result must be entered as an
outpatient LabID event for the ED location for January 2, since the ED location is
included in FacWideIN surveillance and reporting.
EXAMPLE: If monitoring blood specimens only, on January 26, a newly admitted ICU
patient with no previous positive laboratory isolates during this admission has a positive
MRSA urine culture which is not entered as a LabID Events since blood specimens only
are being monitored. The following day, while in the same location, the same patient
has a positive MRSA blood culture. This specimen represents a LabID Event since it is
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a unique blood source (the first MRSA blood isolate for the same patient and same
location). While remaining in ICU, the same patient has another positive blood culture
on February 5. This does not represent a new LabID Event since it has not been >14
days since the most recent MRSA positive blood isolate for this patient and location.
Reporting Instructions: All LabID Events must be reported by location and separately and
independently of Events reported through MDRO Infection Surveillance reporting and/or HAIs
reported through the Device-associated and/or Procedure-associated Modules. See Appendix 1.
Guidance for Handling MDRO and CDI Module Infection Surveillance and LabID Event
Reporting When Also Following Other NHSN Modules for instructions on unique reporting
scenarios. See Appendix 3. Differentiating Between LabID Event and Infection Surveillance for
additional reporting information.
Numerator Data: Data will be reported using the Laboratory-identified MDRO or CDI Event
form (CDC 57.128).
Denominator Data: Patient days, admissions (for inpatient locations), and encounters for
emergency department, observation units, and other affiliated outpatient locations are reported
using the MDRO and CDI Prevention Process and Outcome Measures Monthly Monitoring
form (CDC 57.127). Beginning in 2015 for FacWideIN surveillance, facilities will be required
to enter denominators for all locations physically located in the hospital, as well as
denominators for all locations minus inpatient rehabilitation facility and inpatient psychiatric
facility locations with a separate CCN. The totals should not include other facility types within
the hospital that are enrolled and reporting separately (e.g., LTAC). See Table of Instructions
for completion instructions.
An encounter is defined as a patient visit to an outpatient location. When determining a
patient’s admission dates to both the facility and specific inpatient location, the NHSN user
must take into account any days spent in an inpatient location as an “observation” patient
before being officially admitted as an inpatient to the facility, as these days contribute to
exposure risk. Therefore, all days spent in an inpatient unit, regardless of admission and/or
billing status are included in the counts of admissions and inpatient days for the facility and
specific location; facility and specific location admission dates must be moved back to the first
day spent in the inpatient location. For further information on counting patient days and
admissions, see Appendix 2.
Data Analysis: Based on data provided on the LabID Event form, each event will be
categorized by NHSN to populate different measures. By classifying positive cultures obtained
on day 1 (admission date), day 2, and day 3 of admission as CO LabID Events and positive
cultures obtained on or after day 4 as HO LabID Events, all HO LabID Events will have
occurred more than 48 hours after admission.
The following categorizations and prevalence and incidence calculations are built into the
analysis capabilities of NHSN, and are based on timing of admission to a facility and/or
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location, specimen collection, and location where specimen was collected. Descriptions are
provided to explain how the categories and metrics are defined in NHSN.
Categorizing MDRO LabID Events – Based on Date Admitted to Facility and Date
Specimen Collected:
Community-Onset (CO): LabID Event specimen collected in an outpatient location or an
inpatient location ≤3 days after admission to the facility (i.e., days 1, 2, or 3 of admission).
Healthcare Facility-Onset (HO): LabID Event specimen collected >3 days after admission to
the facility (i.e., on or after day 4).
The following section describes the various measures calculated for MDRO LabID event
surveillance.
Note: Beginning with 2015 data analysis, the number of FacWideIN admissions and number of
FacWideIN patient days used in the various MDRO rate and SIR calculations will reflect data
reported for the facility minus admissions and patient days from inpatient rehabilitation facility
(IRF) and inpatient psychiatric facility (IPF) locations with unique CCNs.
Proxy Measures for Exposure Burden of MDROs – All specimens:
Inpatient Reporting:
 Admission Prevalence Rate = Number of 1st LabID Events per patient per month
identified ≤3 days after admission to the location (if monitoring by inpatient location),
or the facility (if monitoring by overall facility-wide inpatient=FacWideIN) / Number of
patient admissions to the location or facility x 100


Location Percent Admission Prevalence that is Community-Onset = Number of
Admission Prevalent LabID Events to a location that are CO / Total number Admission
Prevalent LabID Events x 100



Location Percent Admission Prevalence that is Healthcare Facility-Onset = Number of
Admission Prevalent LabID Events to a location that are HO / Total number of
Admission Prevalent LabID Events x 100



Overall Patient Prevalence Rate = Number of 1st LabID Events per patient per month
regardless of time spent in location (i.e., prevalent + incident, if monitoring by inpatient
location), or facility (i.e., CO + HO, if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient admissions to the location or facility x 100

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Outpatient Reporting:
 Outpatient Prevalence Rate = Number of 1st LabID Events per patient per month for the
location (if monitoring by outpatient location), or the facility (if monitoring by overall
facility-wide outpatient = FacWideOUT) / Number of patient encounters for the
location or facility x 100
Measures for MDRO Bloodstream Infection: Calculated when monitoring either all
specimens or blood specimens only. NOTE: except for certain locations (i.e., inpatient
rehabilitation facilities, emergency department, and 24-hour observation locations), the Blood
specimens only option can only be used at the FacWideIN and FacWideOUT levels.
MRSA Bloodstream Infection Standardized Infection Ratio (SIR):
The SIR is calculated by dividing the number of observed events by the number of predicted
events. The number of predicted events is calculated using LabID probabilities estimated from
negative binomial models constructed from NHSN data during a baseline time period, which
represents a standard population.4 MRSA Bloodstream Infection SIRs are calculated for
FacWideIN surveillance only.
Note: In the NHSN application, “predicted” is referred to as “expected”.
Note: The SIR will be calculated only if the number of expected events (numExp) is ≥1 to help
enforce a minimum precision criterion.
Facility MRSA Bloodstream Infection Incidence SIR = Number of all unique blood source
LabID Events identified >3 days after admission to the facility (i.e., HO events, when
monitoring by overall facility-wide inpatient = FacWideIN) / Number of expected HO MRSA
blood LabID Events
Inpatient Reporting:
 MDRO Bloodstream Infection Admission Prevalence Rate = Number of all unique
blood source LabID Events per patient per month identified ≤3 days after admission to
the location (if monitoring by inpatient location), or facility (if monitoring by overall
facility-wide inpatient=FacWideIN)/ Number of patient admissions to the location or
facility x 100


MDRO Bloodstream Infection Incidence Rate = Number of all unique blood source
LabID Events per patient per month identified >3 days after admission to the location
(if monitoring by inpatient location), or facility (if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient admissions to the location or facility x 100
(will be removed from NHSN analysis in July 2013)



MDRO Bloodstream Infection Incidence Density Rate = Number of all unique blood
source LabID Events per patient per month identified >3 days after admission to the

January 2016

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MDRO and CDI Module

location (if monitoring by inpatient location), or facility (if monitoring by overall
facility-wide inpatient=FacWideIN) / Number of patient days for the location or facility
x 1,000 (will be referred to in NHSN analysis as Incidence Rate after July 2013)


MDRO Bloodstream Infection Overall Patient Prevalence Rate = Number of 1st Blood
LabID Events per patient per month regardless of time spent in location (i.e., prevalent
+ incident, if monitoring by inpatient location), or facility (i.e., CO + HO, if monitoring
by overall facility-wide inpatient=FacWideIN) / Number of patient admissions to the
location or facility x 100
MRSA Bloodstream Reporting for CMS-certified Inpatient Rehabilitation
Facilities (IRFs) mapped as units within a hospital:
IRF units within a hospital that participate in the CMS Inpatient Rehabilitation Facility
Quality Reporting Program will be given a single MRSA bacteremia Incidence rate for
each type of CMS-certified IRF unit (adult and pediatric) mapped within the hospital
according to CCN.


Inpatient MRSA Bacteremia Incidence Density Rate for IRF units: Number of
all incident blood source MRSA LabID events identified > 3 days after
admission to an IRF unit and where the patient had no positive MRSA
bacteremia LabID events in the prior 14 days in any CMS-certified IRF unit of
that type / Total number of patient days for that type of IRF unit x 1,000

Outpatient Reporting:
 MDRO Bloodstream Infection Outpatient Prevalence Rate = Number of all unique
blood source LabID Events per patient per month for the location (if monitoring by
outpatient location), or the facility (if monitoring by overall facility-wide
outpatient=FacWideOUT) / Number of patient encounters for the location or facility x
100
Measures for MDRO-CRE surveillance: the above incidence and prevalence rates are
calculated separately for each species of CRE (i.e., Klebsiella, E.coli, and Enterobacter) as well
as for all species combined. The following additional metrics is available for CRE LabID event
reporting:
Percent Positive for Carbapenemase: number CRE positive for carbapenemase / number CRE
tested for carbapenemase x 100

Proxy Measures for MDRO Healthcare Acquisition:
 Overall MDRO Infection/Colonization Incidence Rate = Number of 1st LabID Events
per patient per month among those with no documented prior evidence of previous
infection or colonization with this specific organism type from a previously reported
LabID Event, and identified >3 days after admission to the location (if monitoring by
January 2016

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MDRO and CDI Module

inpatient location), or facility (if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient admissions to the location or facility x 100
(will be removed from NHSN analysis in July 2013)


Overall MDRO Infection/Colonization Incidence Density Rate = Number of 1st LabID
Events per patient per month among those with no documented prior evidence of
previous infection or colonization with this specific organism type from a previously
reported LabID Event, and identified >3 days after admission to the location (if
monitoring by inpatient location), or facility (if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient days for the location or facility x 1,000 (will
be referred to in NHSN analysis as Incidence Rate after July 2013)

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MDRO and CDI Module

Clostridium difficile (C. difficile) LabID Event Reporting
Methodology: Facilities may choose to monitor C. difficile where C. difficile testing in the
laboratory is performed routinely only on unformed (i.e., conforming to the shape of the
container) stool samples. C. difficile LabID events may be monitored from all available
inpatient locations as well as all available affiliated outpatient locations where care is provided
to patients post discharge or prior to admission (e.g., emergency departments, outpatient
clinics, and physician offices that submit samples to the facility’s laboratory).
Settings: C. difficile LabID Event reporting can occur in any location: inpatient or outpatient.
Surveillance will NOT be performed in NICU, SCN, babies in LDRP, well-baby nurseries, or
well-baby clinics. If LDRP locations are being monitored, baby counts must be removed.
Requirements: Facilities must choose one or more of the reporting choices listed below and
report data accordingly:
Method
Facility-wide by
location

Denominator Data Reporting
Report separate denominators for each
Enter each CDI LabID Event
location in the facility as specified in
from all locations separately
the NHSN Monthly Reporting Plan
Enter each CDI LabID Event Report separate denominators for each
Selected locations
from selected locations
location monitored as specified in the
separately
NHSN Monthly Reporting Plan
Report aggregate denominator data for
all inpatient locations physically
located in the hospital (e.g., total
number of admissions and total number
Enter each CDI LabID Event
of patient days), as well as
Overall Facilityfrom all inpatient locations
denominators for all inpatient locations
wide Inpatient
AND separately for
minus inpatient rehabilitation facility
(FacWideIN)
outpatient emergency
and inpatient psychiatric facility
department, and 24-hour
locations with separate CCNs. Separate
observation location(s).
denominators should be entered to
capture encounters for each mapped
outpatient emergency department and
24-hour observation location.
Report only one denominator for all
Overall FacilityEnter each CDI LabID Event outpatient locations (e.g., total number
wide Outpatient
from all affiliated outpatient
of encounters including ED and OBS
(FacWideOUT)
locations separately
encounters in addition to other
outpatient locations).
Note: Facilities must indicate each reporting choice chosen for the calendar month on the
Patient Safety Monthly Reporting Plan (CDC 57.106).
January 2016

Numerator Data Reporting

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MDRO and CDI Module

Definitions:
CDI-positive laboratory assay:
A positive laboratory test result for C. difficile toxin A and/or B, (includes molecular assays
[PCR] and/or toxin assays) tested on an unformed stool specimen (must conform to the
container)
OR
A toxin-producing C. difficile organism detected by culture or other laboratory means
performed on an unformed stool sample (must conform to the container).
Duplicate C. difficile-positive test: Any C. difficile toxin-positive laboratory result from the
same patient and location, following a previous C. difficile toxin-positive laboratory result
within the past two weeks [14 days] (even across calendar months and readmissions to the
same facility). There should be 14 days with no C. difficile toxin-positive laboratory result for
the patient and location before another C. difficile LabID Event is entered into NHSN for the
patient and location. The date of specimen collection is considered Day 1. NHSN recommends
each facility keep an internal line listing log of all positive toxin tests as a reference in LabID
event reporting.
EXAMPLE: On January 1, an ICU patient has a C. difficile toxin-positive laboratory result
which is entered into NHSN. On January 4, while in the same location (ICU), the same patient
has another positive C. difficile toxin-positive laboratory result which is not entered into NHSN
because it has not been >14 days since the original C. difficile toxin-positive laboratory result
while in the same location. On January 16, while in the same location (ICU), the same patient
has another C. difficile toxin-positive laboratory result. While it has been more than 14 days
since the initial positive C. difficile toxin-positive laboratory result was entered into NHSN
(January 1) for the same patient and same location, it has not been >14 days since the patient’s
most recent C. difficile toxin-positive laboratory result (January 4) while in the same location.
Therefore, the C. difficile toxin-positive laboratory result for January 16 is not entered into
NHSN. On January 31, the patient has another C. difficile toxin-positive laboratory result while
in the same location (ICU). Since it has been >14 days since the patient’s most recent C.
difficile toxin-positive laboratory result (January 16) while in the same location, this event is
entered into NHSN.
Laboratory-Identified (LabID) Event: All non-duplicate C. difficile toxin-positive laboratory
results. Even if reporting at the FacWide level, all reporting must follow rules by location for
reporting.
Notes:
 A LabID Event calculator is available on the NHSN website to help with data entry
decision making around the 14-day rule.
 If a facility is participating in FacWideIN surveillance and reporting, the facility must also
conduct separate location-specific surveillance in all outpatient emergency department and
24-hour observation locations. This means LabID Events for the same organism and LabID
January 2016

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MDRO and CDI Module



Event type must be reported from these locations even if the patient is not subsequently
admitted to an inpatient location during the same encounter.
All emergency department and 24-hour observation locations must be identified and
mapped as outpatient locations within NHSN. For more information about mapping
locations, see Chapter 15 in the NHSN manual.

Reporting Instructions: All C. difficile LabID Events must be reported by location and
separately and independently of Events reported using the C. difficile Infection Surveillance
reporting option and/or HAI reporting.
Numerator: Data will be reported using the Laboratory-Identified MDRO or CDI Event form
(CDC 57.128).
Denominator Data: Patient days, admissions (for inpatient locations), and encounters for
emergency departments, observation units, and other affiliated outpatient locations are reported
using the MDRO and CDI Prevention Process and Outcome Measures Monthly Monitoring
form (CDC 57.127). See Tables of Instructions for completion instructions. Beginning in 2015
for FacWideIN surveillance, facilities will be required to enter denominators for all locations
physically located in the hospital, as well as denominators for all locations minus inpatient
rehabilitation facility and inpatient psychiatric facility locations with a separate CCN. The
totals should not include other facility types within the hospital that are enrolled and reporting
separately (e.g., LTAC). See Tables of Instructions for completion instructions.
An encounter is defined as a patient visit to an outpatient location for care. When determining a
patient’s admission dates to both the facility and specific inpatient location, the NHSN user
must take into account all days, including any days spent in an inpatient location as an
“observation” patient before being officially admitted as an inpatient to the facility, as these
days contribute to exposure risk. Therefore, all days spent in an inpatient unit, regardless of
admission and/or billing status are included in the counts of admissions and inpatient days for
the facility and specific location; facility and specific location admission dates must be moved
back to the first day spent in the inpatient location. For further information on counting patient
days and admissions, see Appendix 2: Determining Patient Days for Summary Data
Collection: Observation vs. Inpatients
CDI Data Analysis: Based on data provided on the LabID Event form, each event will be
categorized by NHSN to populate different measures. Positive toxin tests obtained on hospital
day 1 (admission date), hospital day 2 or hospital day 3 are classified as CO events. Positive
toxin tests obtained on or after hospital day 4 are classified as HO LabID Events.
The following categorizations and prevalence and incidence calculations are built into the
analysis capabilities of NHSN, and are based on timing of admission to a facility and/or
location, specimen collection, and location where specimen was collected. Descriptions are
provided to explain how the categories and metrics are defined in NHSN.

January 2016

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MDRO and CDI Module

Categorization Based on Current Date Specimen Collected and Prior Date Specimen
Collected of a previous CDI LabID Event:
 Incident CDI Assay: Any CDI LabID Event from a specimen obtained >8 weeks after
the most recent CDI LabID Event (or with no previous CDI LabID Event documented)
for that patient.


Recurrent CDI Assay: Any CDI LabID Event from a specimen obtained >2 weeks and
≤8 weeks after the most recent CDI LabID Event for that patient.

Note: Beginning in 2015, for FacWideIN surveillance, CDI Assay is assigned based on Events
from inpatient locations, emergency departments, and 24-hour observation locations. For data
reported prior to 2015, CDI Assay was assigned based on events from within the same setting
only. For example, in 2014, if performing both FacWideIN and FacWideOUT surveillance,
CDI Assay of inpatient CDI LabID Events was determined by a review of previously-entered
CDI LabID Events from inpatient locations only.
The incident and recurrent CDI LabID Events are further categorized within NHSN. The
following categorizations, as well as prevalence and incidence calculations are built into the
analysis capabilities of NHSN, and are based on timing of admission to facility and/or location,
specimen collection, location where specimen was collected, and previous discharge.
Descriptions are provided to explain how the categories and metrics are defined in NHSN.
Categorizing CDI LabID Events – Based on Date Admitted to Facility and Date Specimen
Collected:
 Community-Onset (CO): LabID Event collected in an outpatient location or an inpatient
location ≤3 days after admission to the facility (i.e., days 1, 2, or 3 of admission).


Community-Onset Healthcare Facility-Associated (CO-HCFA): CO LabID Event
collected from a patient who was discharged from the facility ≤4 weeks prior to current
date of stool specimen collection. Data from outpatient locations (e.g., outpatient
encounters) are not included in this definition.



Healthcare Facility-Onset (HO): LabID Event collected >3 days after admission to the
facility (i.e., on or after day 4).

The following section describes the various measures calculated for CDI LabID event
surveillance.
Note: Beginning with 2015 data, the number of FacWideIN admissions and number of
FacWideIN patient days used in the various CDI rate and SIR calculations will represent those
reported for the facility minus admissions and patient days from the following: locations with
unique CCNs (i.e., IRF and IPF units) separate from the reporting facility, neonatal ICUs,
special care nurseries, and well-baby locations.

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MDRO and CDI Module

CDI Standardized Infection Ratio (SIR):
The SIR is calculated by dividing the number of observed events by the number of predicted
events. The number of predicted events is calculated using LabID probabilities estimated from
negative binomial models constructed from NHSN data during a baseline time period, which
represents a standard population. CDI SIRs are calculated for FacWideIN surveillance only.4
Note: In the NHSN application, “predicted” is referred to as “expected”.
Note: The SIR will be calculated only if the number of expected events (numExp) is ≥1, to help
enforce a minimum precision criterion. The CDI SIRs are only calculated at the quarter level or
higher. In addition, SIRs will not be calculated for a quarter until the CDI Test type has been
reported. When the “MDRO/CDI Prevention Process and Outcome Measures Monthly
Reporting” form is completed for the last month of each quarter, users are asked to report the
primary type of test that was used to identify CDI in the hospital for that quarter. That test type
is then used in the calculation of the CDI SIR for that quarter. More information about the
calculation of the CDI SIR can be found here: http://www.cdc.gov/nhsn/pdfs/mrsacdi/riskadjustment-mrsa-cdi.pdf

Facility CDI Incidence SIR = Number of all Incident CDI LabID Events identified >3 days
after admission to the facility (i.e., HO events when monitoring by overall facility-wide
inpatient = FacWideIN) / Number of expected Incident HO CDI LabID Events

Calculated CDI Prevalence Rates:
Inpatient Reporting:
 Admission Prevalence Rate = Number of non-duplicate CDI LabID Events per patient
per month identified ≤3 days after admission to the location (if monitoring by inpatient
location), or facility (if monitoring by overall facility-wide inpatient=FacWideIN)
(includes CO and CO-HCFA events) / Number of patient admissions to the location or
facility x 100


Community-Onset Admission Prevalence Rate = Number of CDI LabID events that are
CO, per month, in the facility / Number of patient admissions to the facility x 100 (this
calculation is only accurate for Overall Facility-wide Inpatient reporting)



Location Percent Admission Prevalence that is Community-Onset = Number of
Admission Prevalent LabID Events to a location that are CO / Total number Admission
Prevalent LabID Events x 100 (Note: The numerator in this formula does not include
Admission Prevalent LabID Events that are CO-HFCA.)

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MDRO and CDI Module



Location Percent Admission Prevalence that is Community-Onset Healthcare FacilityAssociated = Number of Admission Prevalent LabID Events to a location that are COHCFA / Total number Admission Prevalent LabID Events x 100



Location Percent Admission Prevalence that is Healthcare Facility-Onset = Number of
Admission Prevalent LabID Events to a location that are HO / Total number of
Admission Prevalent LabID Events x 100



Overall Patient Prevalence Rate = Number of 1st CDI LabID Events per patient per
month regardless of time spent in location (i.e., prevalent + incident, if monitoring by
inpatient location), or facility (i.e., CO + CO-HCFA + HO, if monitoring by overall
facility-wide inpatient=FacWideIN) / Number of patient admissions to the location or
facility x 100

Outpatient Reporting:
 Outpatient Prevalence Rate = Number of all non-duplicate CDI LabID Events per
patient per month for the location (if monitoring by outpatient location), or the facility
(if monitoring by overall facility-wide outpatient=FacWideOUT) / Number of patient
encounters for the location or facility x 100
Calculated CDI Incidence Rates: (see categorization of Incident, HO, and CO-HCFA above).


Location CDI Incidence Rate = Number of Incident CDI LabID Events per month
identified >3 days after admission to the location / Number of patient days for the
location x 10,000



Facility CDI Healthcare Facility-Onset Incidence Rate = Number of all Incident HO
CDI LabID Events per month in the facility/ Number of patient days for the facility x
10,000 (this calculation is only accurate for Overall Facility-wide Inpatient reporting)



Facility CDI Combined Incidence Rate = Number of all Incident HO and CO-HCFA
CDI LabID Events per month in the facility / Number of patient days for the facility x
10,000 (this calculation is only accurate for Overall Facility-wide Inpatient reporting)

C.difficile Reporting for CMS-certified Inpatient Rehabilitation Facilities (IRFs) mapped
as units within a hospital:
IRF units within a hospital that participate in the CMS Inpatient Rehabilitation Facility Quality
Reporting Program will be given a single CDI LabID event Incidence rate for each type of
CMS-certified IRF unit (adult and pediatric) mapped within the hospital according to CCN.


January 2016

Inpatient CDI Incidence Density Rate for IRF units: Number of all incident CDI
LabID events identified > 3 days after admission to an IRF unit and where the
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MDRO and CDI Module

patient had no positive CDI LabID events in the prior 14 days in any CMScertified IRF unit of that type / Total number of patient days for that type of IRF
unit x 10,000

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MDRO and CDI Module

Figure 1. MDRO Test Result Algorithm for All Specimens Laboratory-Identified (LabID) Events
MDRO isolate from any specimen (except AST
specimens) per patient and location

1st in calendar
month per
patient, per
location, per
MDRO

Yes

LabID Event
(Non-duplicate
isolate)

No

Duplicate MDRO
isolate

Source =
Blood for
patient
and same
location

No
Not a
LabID
Event

Yes

Prior (+) same
MDRO from blood
in ≤2 weeks from
same location
(including across
calendar months)

No
LabID Event (Unique blood
source MDRO)

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Yes

Not a
LabID
Event

MDRO and CDI Module

Figure 2. MDRO Test Result Algorithm for Blood Specimens Only Laboratory-Identified (LabID) Events

MDRO isolate from blood per
patient and location

No

Prior (+) same
MDRO from
blood in ≤2 weeks
from same patient
and location
(including across
calendar months)

Duplicate
MDRO test

LabID Event

January 2016

Yes

12 - 24

Not a LabID
Event

MDRO and CDI Module

Figure 3. C. difficile Test Result Algorithm for Laboratory Identified (LabID) Events

(+) C. difficile test result
per patient and location

Prior (+) in ≤2
weeks from same
patient and
location
(including across
calendar months)
No

Yes

Duplicate C.
difficile test

LabID Event

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Not a LabID
Event

MDRO and CDI Module

Option 2: Infection Surveillance Reporting
Introduction: The Infection Surveillance reporting option for MDRO and C. difficile infections enables
users to utilize the CDC/NHSN healthcare-associated infections definitions for identifying and reporting
infections associated with MDROs and/or C. difficile. Surveillance must occur from at least one patient care
area and requires active, patient-based, prospective surveillance of the chosen MDRO(s) and/or C. difficile
infections (CDIs) by a trained Infection Preventionists (IP). This means that the IP shall seek to confirm
and classify infections caused by the chosen MDRO(s) and/or C. difficile for monitoring during a patient’s
stay in at least one patient care location during the surveillance period. These data will enhance the ability of
NHSN to aggregate national data on MDROs and CDIs.
A. MDRO Infection Surveillance Reporting
Methodology: Facilities may choose to monitor one or more of the following MDROs: MRSA, MRSA and
MSSA, VRE, CephR- Klebsiella, CRE (CRE-Klebsiella, CRE-E. coli, and CRE-Enterobacter), and
multidrug-resistant Acinetobacter spp. (See definitions in Section I, Option 1A). For S. aureus, both the
resistant (MRSA) and the susceptible (MSSA) phenotypes can be tracked to provide concurrent measures of
the susceptible pathogens as a comparison to those of the resistant pathogens in a setting of active MRSA
prevention efforts. REMEMBER: No Active Surveillance Culture/Testing (ASC/AST) results are to be
included in this reporting of individual results.
Settings: Infection Surveillance can occur in any inpatient location where such infections may be identified
and where denominator data can be collected, which may include critical/intensive care units (ICU),
specialty care areas (SCA), neonatal units, step-down units, wards, and chronic care units. In Labor,
Delivery, Recovery, & Post-partum (LDRP) locations, where mom and babies are housed together, users
must count both mom and baby in the denominator. If moms only are being counted, then multiply moms
times two to include both mom and baby in denominators.
Requirements: Surveillance for all types of NHSN-defined healthcare-associated infections (HAIs),
regardless if HAI is included in “in-plan” or “off- plan” surveillance, of the MDRO selected for monitoring
in at least one location in the healthcare facility as indicated in the Patient Safety Monthly Reporting Plan
(CDC 57.106).
Definitions: MDROs included in this module are defined in Section I, Option 1A. Refer to CDC/NHSN
Surveillance Definitions for Specific Types of Infections for infection site criteria.
Location of Attribution and Transfer Rule applies – See Identifying HAIs in NHSN chapter (Chapter 2).
Reporting Instructions: If participating in MDRO/CDI Infection Surveillance and/or LabID Event
Reporting, along with the reporting of HAIs through the Device-Associated and/or Procedure-Associated
Modules, see Appendix 1: Guidance for Handling MDRO/CDI Module Infection Surveillance and LabID
Event Reporting When Also Following Other NHSN Modules, for instructions on unique reporting scenarios.

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MDRO and CDI Module

Numerator Data: Number of healthcare-associated infections, by MDRO type. Infections are reported on
the appropriate NHSN forms: Primary Bloodstream Infection, Pneumonia, Ventilator-Associated Event,
Urinary Tract Infection, Surgical Site Infection, or MDRO or CDI Infection Event (CDC 57.108, 57.111,
57.112, 57.114, 57.120, and 57.126, respectively.). See the Table of Instructions, located in each of the
applicable chapters, for completion instructions.
Denominator Data: Number of patient days and admissions. Patient days and admissions are reported by
location using the MDRO and CDI Prevention Process and Outcome Measures Monthly Monitoring form
(CDC 57.127). See Table of Instructions for completion instructions.
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and patient care location.
MDRO Infection Incidence Rate = Number of HAIs by MDRO type/ Number of patient days x 1000
B. Clostridium difficile Infection Surveillance Reporting
Methodology: C. difficile Infection (CDI) Surveillance, reporting on all NHSN-defined healthcareassociated CDIs from at least one patient care area, is one reporting option for C. difficile (i.e., part of your
facility’s Monthly Reporting Plan). These data will enhance the ability of NHSN to aggregate national data
on CDIs.
Settings: Infection Surveillance will occur in any inpatient location where denominator data can be
collected, which may include critical/intensive care units (ICU), specialty care areas (SCA), step-down
units, wards, and chronic care units. Surveillance will NOT be performed in Neonatal Intensive Care Units
(NICU), Specialty Care Nurseries (SCN), babies in LDRP, or well-baby nurseries. If LDRP locations are
being monitored, baby counts must be removed.
Requirements: Surveillance for CDI must be performed in at least one location in the healthcare institution
as indicated in the Patient Safety Monthly Reporting Plan (CDC 57.106).
Definitions: Report all healthcare-associated infections where C. difficile, identified by a positive toxin
result, including toxin producing gene [PCR]), is the associated pathogen, according to the Repeat Infection
Timeframe (RIT) rule for HAIs (See Identifying HAIs in NHSN chapter). Refer to specific definitions in
CDC/NHSN Surveillance Definitions for Specific Types of Infections chapter for C. difficile gastrointestinal
system infection (GI-CDI).
HAI cases of CDI that meet criteria for a healthcare-associated infection should be reported as Clostridium
difficile gastrointestinal system infection (GI-CDI). Report the pathogen as C. difficile on the MDRO or CDI
Infection Event form (CDC 57.126). If the patient develops GI-CDI, and GI-GE or GI-GIT, report the GICDI and the GI-GE or GI-GIT only if additional enteric organisms are identified and applicable criteria are
met. Note: CDI laboratory-identified event (LabID Event) categorizations (e.g., recurrent CDI assay,
incident CDI assay, healthcare facility-onset, community-onset, community-onset healthcare facilityassociated) do not apply to HAIs; including C. difficile associated gastrointestinal system infections (GI-

January 2016

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MDRO and CDI Module

CDI). Each new GI-CDI must be reported according to the HAI rules outlined in Identifying HAIs in NHSN
chapter.
CDI Complications: CDI in a case patient within 30 days after CDI symptom onset with at least one of the
following:
1. Admission to an intensive care unit for complications associated with CDI (e.g., for shock that
requires vasopressor therapy);
2. Surgery (e.g., colectomy) for toxic megacolon, perforation, or refractory colitis
AND/OR
3. Death caused by CDI within 30 days after symptom onset and occurring during the hospital
admission.
Location of Attribution and Transfer Rule apply to Infection Surveillance – See Identifying HAIs in NHSN
chapter.
Numerator Data: Number of healthcare-associated C. difficile infections. Infections are reported on the
MDRO or CDI Infection Event form (CDC 57.126). See Tables of Instructions for completion instructions.
Denominator Data: Number of patient days and admissions by location are reported using the MDRO and
CDI and Outcome Measures Monthly Monitoring form (CDC 57.127). See Tables of Instructions for
completion instructions.
C. difficile Infections:
Numerator: The total number of HAI CDI cases identified during the surveillance month for a
location.
Denominator: The total number of patient days and admissions during the surveillance month for a
location.
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and by patient care location.
C. difficile Infection Incidence Rate = Number of HAI CDI cases / Number of patient days x 10,000

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MDRO and CDI Module

II.

Supplemental Reporting

1. Prevention Process Measures Surveillance
a. Monitoring Adherence to Hand Hygiene
Introduction: This option will allow facilities to monitor adherence to hand hygiene after a healthcare
worker (HCW) has contact with a patient or inanimate objects in the immediate vicinity of the patient.
Research studies have reported data suggesting that improved after-contact hand hygiene is associated with
reduced MDRO transmission. While there are multiple opportunities for hand hygiene during patient care,
for the purpose of this option, only hand hygiene after contact with a patient or inanimate objects in the
immediate vicinity of the patient will be observed and reported. (http://www.cdc.gov/handhygiene/)
Settings: Surveillance will occur in any location: inpatient or outpatient.
Requirements: Surveillance for adherence to hand hygiene in at least one location in the healthcare
institution for at least one calendar month as indicated in the Patient Safety Monthly Reporting Plan (CDC
57.106). This should be done in patient care locations also selected for Infection Surveillance or LabID
Event reporting.
In participating patient care locations, perform at least 30 different unannounced observations after contact
with patients for as many individual HCWs as possible. For example, try to observe all types of HCWs
performing a variety of patient care tasks during the course of the month, not only nurses, or not only during
catheter or wound care. No personal identifiers will be collected or reported.
Definitions:
Antiseptic handwash: Washing hands with water and soap or other detergents containing an antiseptic
agent.
Antiseptic hand-rub: Applying an antiseptic hand-rub product to all surfaces of the hands to reduce the
number of microorganisms present.
Hand hygiene: A general term that applies to either: handwashing, antiseptic hand wash, antiseptic hand
rub, or surgical hand antisepsis.
Handwashing: Washing hands with plain (i.e., non-antimicrobial) soap and water.
Numerator: Hand Hygiene Performed = Total number of observed contacts during which a HCW touched
either the patient or inanimate objects in the immediate vicinity of the patient and appropriate hand hygiene
was performed.
Denominator: Hand Hygiene Indicated = Total number of observed contacts during which a HCW touched
either the patient or inanimate objects in the immediate vicinity of the patient and therefore, appropriate
hand hygiene was indicated.

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MDRO and CDI Module

Hand hygiene process measure data are reported using the MDRO and CDI Prevention Process and
Outcome Measures Monthly Monitoring form (CDC 57. 127). See Tables of Instructions for completion
instructions.
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and patient care location.
Hand Hygiene Percent Adherence = Number of contacts for which hand hygiene was performed / Number
of contacts for which hand hygiene was indicated x 100
b. Monitoring Adherence to Gown and Gloves Use as Part of Contact Precautions
Introduction: This option will allow facilities to monitor adherence to gown and gloves use when a HCW
has contact with a patient or inanimate objects in the immediate vicinity of the patient, when that patient is
on Transmission-based Contact Precautions. While numerous aspects of adherence to Contact Precautions
could be monitored, this surveillance option is only focused on the use of gown and gloves.
(http://www.cdc.gov/ncidod/dhqp/gl_isolation_contact.html)
Settings: Surveillance can occur in any of 4 types of inpatient locations: (1) intensive care units (ICU), (2)
specialty care areas, (3) neonatal intensive care units (NICU), and (4) any other inpatient care location in the
institution (e.g., surgical wards).
Requirements: Surveillance for adherence to gown and gloves use in at least one location in the healthcare
institution for at least 1 calendar month as indicated in the Patient Safety Monthly Reporting Plan (CDC
57.106). Ideally, this should be done in patient care locations also selected for Infection Surveillance or
LabID Event reporting.
Among patients on Transmission-based Contact Precautions in participating patient care locations, perform
at least 30 unannounced observations. A total of thirty different contacts must be observed monthly among
HCWs of varied occupation types. For example, try to observe all types of HCWs performing a variety of
patient care tasks during the course of the month, not only nurses, or not only during catheter or wound care.
Both gown and gloves must be donned appropriately prior to contact for compliance. No personal
identifiers will be collected or reported.
Definitions:
Gown and gloves use: In the context of Transmission-based Contact Precautions, the donning of both a
gown and gloves prior to contact with a patient or inanimate objects in the immediate vicinity of the patient.
Both a gown and gloves must be donned appropriately prior to contact for compliance.
Numerator: Gown and Gloves Used = Total number of observed contacts between a HCW and a patient or
inanimate objects in the immediate vicinity of a patient on Transmission-based Contact Precautions for
which gown and gloves had been donned appropriately prior to the contact.

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MDRO and CDI Module

Denominator: Gown and Gloves Indicated = Total number of observed contacts between a HCW and a
patient on Transmission-based Contact Precautions or inanimate objects in the immediate vicinity of the
patient and therefore, gown and gloves were indicated.
Gown and gloves use process measure data are reported using the MDRO and CDI Prevention Process and
Outcome Measures Monthly Monitoring form (CDC 57.127). See Tables of Instructions for completion
instructions.
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and patient care location.
Gown and Glove Use Percent Adherence = Number of contacts for which gown and gloves were used
appropriately / Number of contacts for which gown and gloves were indicated x 100
c. Monitoring Adherence to Active Surveillance Testing
Introduction: This option will allow facilities to monitor adherence to active surveillance testing (AST) of
MRSA and/or VRE, using culturing or other methods.
Settings: Surveillance will occur in any of 4 types of inpatient locations: (1) intensive care units (ICU),
(2) specialty care areas, (3) neonatal intensive care units (NICU), and (4) any other inpatient care location in
the institution (e.g., surgical wards).
Requirements: Surveillance of AST adherence in at least one location in the healthcare facility for at least
one calendar month as indicated in the Patient Safety Monthly Reporting Plan (CDC 57.106). A facility may
choose to report AST for MRSA and/or VRE in one or multiple patient care locations, as the facility deems
appropriate. Ideally, this should be done in patient care locations also selected for Infection Surveillance or
LabID Event reporting. To improve standardization of timing rules for AST specimen collection, classify
admission specimens as those obtained on day 1 (admission date), day 2, or day 3 (i.e., ≤3 days). Classify
discharge/transfer AST specimens as those collected on or after day 4 (i.e., >3 days).
Definitions:
AST Eligible Patients: Choose one of two methods for identifying patients that are eligible for AST:
All = All patients in the selected patient care area regardless of history of MRSA or VRE infection
or colonization.
OR
NHx = All patients in the selected patient care area who have NO documented positive MRSA or
VRE infection or colonization during the previous 12 months (as ascertained by either a facility’s
laboratory records or information provided by referring facilities); and no evidence of MRSA or
VRE during stay in the patient care location (i.e., they are not in Contact Precautions).
Timing of AST: Choose one of two methods for reporting the timing of AST:
Adm = Specimens for AST obtained ≤3 days after admission,
OR
Both = Specimens for AST obtained ≤3 days after admission and, for patients’ stays of >3 days, at
the time of discharge/transfer. Discharge/transfer AST should include all discharges (including

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MDRO and CDI Module

discharges from the facility or to other wards or deaths) and can include the most recent weekly AST
if performed >3 days after admission to the patient care location. Discharge/transfer AST should not
be performed on patients who tested positive on AST admission.
Numerator and Denominator Data: Use the MDRO and CDI Prevention Process and Outcome Measures
Monthly Monitoring form (CDC 57.127) to indicate: 1) AST was performed during the month for MRSA
and/or VRE, 2) AST-eligible patients, and 3) the timing of AST. No personal identifiers will be collected or
reported. See Tables of Instructions for completion instructions.
Numerator: For each month during which AST is performed:
Admission AST Performed = Number of patients eligible for admission AST who had a specimen
obtained for testing ≤3 days after admission,
AND/OR
Discharge/Transfer AST Performed = For patients’ stays >3 days, the number of discharged or
transferred patients eligible for AST who had a specimen obtained for testing prior to discharge, not
including the admission AST.
Denominator: For each month during which AST is performed:
Admission AST Eligible = Number of patients eligible for admission AST (All or NHx),
AND/OR
Discharge/Transfer AST Eligible = Number of patients eligible for discharge/transfer AST (All or
NHx) AND in the facility location >3 days AND negative if tested on admission.
Data Analysis: Data are stratified by patient care location and time (e.g., month, quarter, etc.), according to
AST-eligible patients monitored and the timing of AST.
Admission AST Percent Adherence = Number of patients with admission AST Performed / Number of
patients admission AST eligible x 100
Discharge/transfer AST Percent Adherence = Number of patients with discharge/transfer AST performed /
Number of patients discharge/transfer AST eligible x 100

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MDRO and CDI Module

2. Active Surveillance Testing Outcome Measures
Introduction: This option will allow facilities to use the results of AST to monitor the prevalent and
incident rates of MRSA and/or VRE colonization or infection. This information will assist facilities in
assessing the impact of intervention programs on MRSA or VRE transmission.
Settings: Surveillance will occur in any of 4 types of inpatient locations: (1) intensive care units (ICU), (2)
specialty care, (3) neonatal intensive care units (NICU), and (4) any other inpatient care location in the
institution (e.g., surgical wards).
Requirements: Surveillance for prevalent and/or incident MRSA or VRE cases in at least one location in
the healthcare facility for at least one calendar month as indicated in the Patient Safety Monthly Reporting
Plan (CDC 57.106). This can be done ONLY in locations where AST adherence is being performed. A
minimum AST adherence level will be required for the system to calculate prevalence and incidence. A
facility may choose to report AST for MRSA and/or VRE in one or multiple patient care locations, as the
facility deems appropriate. Ideally, this should be done in patient care locations also selected for Infection
Surveillance or LabID Event reporting. To improve standardization of timing rules for AST specimen
collection, classify admission specimens as those obtained on day 1 (admission date), day 2, or day 3 (i.e.,
≤3 days). Classify discharge/transfer AST specimens as those collected on or after day 4 (i.e., >3 days).
Only the first specimen positive for MRSA or VRE from a given patient in the patient care location is
counted, whether obtained for AST or as part of clinical care. If an Admission AST specimen is not
collected from an eligible patient, assume the patient has no MRSA or VRE colonization.
Definitions:
AST Admission Prevalent case:
Known Positive = A patient with documentation on admission of MRSA or VRE colonization or
infection in the previous 12 months (i.e., patient is known to be colonized or infected as ascertained
by either a facility’s laboratory records or information provided by referring facilities). (All MRSA
or VRE colonized patients currently in a location during the month of surveillance should be
considered “Known Positive”),
OR
Admission AST or Clinical Positive = A patient with MRSA or VRE isolated from a specimen
collected for AST ≤3 days after admission or from clinical specimen obtained ≤3 days after
admission (i.e., MRSA or VRE cannot be attributed to this patient care location).
AST Incident case: A patient with a stay >3 days:
With no documentation on admission of MRSA or VRE colonization or infection during the
previous 12 months (as ascertained either by the facility’s laboratory records or information
provided by referring facilities); including admission AST or clinical culture obtained ≤3 days after
admission (i.e., patient without positive specimen),
AND
With MRSA or VRE isolated from a specimen collected for AST or clinical reasons > 3 days after
admission to the patient care location or at the time of discharge/transfer from the patient care
location (including discharges from the facility or to other locations or deaths).

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MDRO and CDI Module

MRSA colonization: Carriage of MRSA without evidence of infection (e.g., nasal swab test positive for
MRSA, without signs or symptoms of infection).
AST Eligible Patients: Choose one of two methods for identifying patients’ eligible for AST:
All = All patients in the selected patient care area regardless of history of MRSA or VRE infection
or colonization,
OR
NHx = All patients in the selected patient care area who have NO documented positive MRSA or
VRE infection or colonization during the previous 12 months (as ascertained either by the facility’s
laboratory records or information provided by referring facilities); and no evidence of MRSA or
VRE during stay in the patient care location.
Timing of AST: Choose one of two methods for reporting the timing of AST:
Adm = Specimens for AST obtained ≤3 days after admission,
OR
Both = Specimens for AST obtained ≤3 days after admission and, for patients’ stays of >3 days, at
the time of discharge/transfer. Discharge/transfer AST should include all discharges (including
discharges from the facility or to other wards or deaths) and can include the most recent weekly AST
if performed >3 days after admission to the patient care location. Discharge/transfer AST should not
be performed on patients who tested positive on AST admission.
Numerator and Denominator Data: Use the MDRO and CDI Prevention Process and Outcome Measures
Monthly Monitoring form (CDC 57.127) to indicate: 1) AST outcomes monitoring and adherence was
performed during the month for MRSA and/or VRE, 2) AST eligible patients, and 3) the timing of AST. No
personal identifiers will be collected or reported. See Tables of Instructions for completion instructions.
If only admission AST is performed, only prevalent cases of MRSA or VRE can be detected in that patient
care location. If both admission and discharge/transfer AST are performed, both prevalent and incident
cases can be detected. No personal identifiers will be collected or reported.
Admission Prevalent Case:
Numerator Sources: (1) Known Positive; (2) Admission AST or Clinical Positive = Cases ≤3 days after
admission
Denominator Source: Total number of admissions
Incident Case:
Numerator: Discharge/transfer AST or Clinical Positive = Cases >3 days after admission and without
positive test result(s) on admission
Denominator: Total number of patient days

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MDRO and CDI Module

Note: For research purposes calculating patient-days at risk (i.e., excluding patient-days in which patients
were known to be MRSA or VRE colonized or infected) may be a preferable denominator, but for
surveillance purposes and ease of aggregating, total number of patient days is required for this module.
Data Analysis: Data are stratified by patient care location and time (e.g., month, quarter, etc.) according to
the eligible patients monitored and timing of AST.
AST Admission Prevalence rate =
For Eligible patients = All:
Number of admission AST or clinical positive / Number of admissions x 100
For Eligible patients = NHx:
Number of admission AST or clinical positive + Number of known positive / Number of admissions x 100
AST Incidence rate = Number of discharge/transfer AST or clinical positive / Number of patient days x
1000

1

HICPAC, Management of Multidrug-Resistant Organisms in Healthcare Settings.
.
2

Cohen AL, et al. Infection Control and Hospital Epidemiology. Oct 2008; 29:901-913.

3

McDonald LC, Coignard B, Dubberke E, Song X. Horan T, Kutty PK. Recommendations for surveillance of Clostridium
difficile-associated disease. Infection Control Hospital Epidemiology 2007; 28:140-5.
4

Dudeck MA, Weiner LM, Malpiedi PJ, et al. Risk Adjustment for Healthcare Facility-Onset C. difficile and MRSA Bacteremia
Laboratory-identified Event Reporting in NHSN. Published March 12, 2013. Available at: http://www.cdc.gov/nhsn/pdfs/mrsacdi/RiskAdjustment-MRSA-CDI.pdf.
6

Cohen SH, Gerding DN, Johnson S, Kelly CP, Loo VG, McDonald LC, et al. Clinical practice guidelines for Clostridium
difficile infection in adults: 2010 update by the Society for Healthcare Epidemiology of America (SHEA) and the Infectious
Diseases Society of America (IDSA). Infection Control and Hospital Epidemiology 2010; 31:431-455.

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MDRO and CDI Module

Table 2. Measures Delivered to CMS For Facilities Participating in Quality Reporting Programs:
MRSA Bacteremia and C.difficile LabID Events
Facility Type

CMS Quality
Reporting Program

MRSA Bacteremia
LabID Event Measure
Sent to CMS

C.difficile LabID Event
Measure Sent to CMS

General Acute Care
Hospitals

Inpatient Quality
Reporting Program

MRSA Bloodstream
Infection SIR (FacWideIN)

Facility CDI Incidence SIR
(FacWideIN)

Long Term Care Hospitals
(referred to as Long Term
Acute Care Hospitals in
NHSN)

Long Term Care
Hospital Quality
Reporting Program

MRSA Bloodstream
Infection Incidence Density
Rate (FacWideIN)

Facility CDI Healthcare
Facility-Onset Incidence
Rate (FacWideIN)

IRF units within a hospital:
MRSA Bloodstream
Infection Incidence Density
Rate for IRF Units

IRF units within a
hospital: CDI Incidence
Density Rate for IRF Units

Free-standing IRFs: MRSA
Bloodstream Infection
Incidence Density Rate
(FacWideIN)

Free-standing IRFs:
Facility CDI Healthcare
Facility-Onset Incidence
Rate (FacWideIN)

MRSA Bloodstream
Infection Incidence Density
Rate (FacWideIN)

Facility CDI Healthcare
Facility-Onset Incidence
Rate (FacWideIN)

Inpatient Rehabilitation
Facilities (IRFs)

PPS-Exempt Cancer
Hospital

January 2016

Inpatient Rehabilitation
Facility Quality
Reporting Program

PPS-Exempt Cancer
Hospital Quality
Reporting (PCHQR)
Program

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MDRO and CDI Module

Appendix 1. Guidance for Handling MDRO and CDI Module Infection Surveillance and LabID
Event Reporting When Also Following Other NHSN Modules
If a facility is monitoring CLABSIs, CAUTIs, VAPs, or VAEs within the Device-Associated Module and/or
SSIs within the Procedure-Associated Module and is also monitoring MDROs (e.g., MRSA) in the MDRO
and CDI Module, then there are a few situations where reporting the infection or LabID event may be
confusing. The following scenarios provide guidance to keep the counts and rates consistent throughout
your facility and between all of the NHSN Modules. These rules apply to the reporting of “Big 5”
infections (BSI, UTI, PNEU, VAE, and SSI) caused by an MDRO selected for monitoring.
Device-Associated Module with MDRO and CDI Module
Scenario 1: Facility is following CLABSI, CAUTI, VAP, or VAE along with MDRO Infection Surveillance
and possibly LabID Event Reporting in the same location:
Healthcare-associated Infection identified for this location.
1. Report the infection (BSI, UTI, PNEU, or VAE).
2. Answer “Yes” to the MDRO infection question.
This fulfills the infection reporting requirements of both modules in one entry and lets the NHSN reporting
tool know that this infection should be included in both the Device-Associated and the MDRO infection
datasets and rates.
3. If following LabID event reporting in the same location, report also (separately) as a LabID Event (if
meets the MDRO protocol criteria for LabID event).

Scenario 2: Facility is following BSI (CLABSI), UTI (CAUTI), PNEU/VAP, or VAE along with MDRO
Infection Surveillance and possibly LabID Event Reporting in multiple locations:
The event date for the infection is the day of patient transfer from one location (the transferring location) to
another location (the new location), or the next day.
1. Report the infection (BSI, UTI, PNEU and VAE) and attribute to the transferring location, if
transferring location was following that Event Type (BSI, UTI, PNEU, VAE) on the day of Event,
which occurred on the date of transfer, or the following day.
2. Answer “Yes” to the MDRO infection question, if the transferring location was following that
MDRO on the day of Event, which occurred on the date of transfer, or the following day.
3. If, on the date of culture collection, the new location is following LabID event reporting, report also
(separately) as a LabID Event and attribute to the new location (if meets the MDRO protocol criteria
for LabID event).

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MDRO and CDI Module

Procedure-Associated Module with MDRO and CDI Module
Note: SSIs are associated with a procedure and not a patient location, but MDROs are connected with the
patient location.
Scenario 3: Facility is following SSI along with MDRO Infection Surveillance and possibly LabID Event
Reporting:
Patient has surgery, is transferred to a single unit for the remainder of the stay, and during the current stay
acquires an SSI.
1. Report the infection (SSI) and attribute to the post-op location.
2. Answer “Yes” to the MDRO infection question, if the post-op location is following that MDRO
during the month of the date of event.
3. If following LabID event reporting in the post-op location, report also (separately) as a LabID Event
(if meets the MDRO protocol criteria for LabID event).
Scenario 4: Facility is following SSI along with MDRO Infection Surveillance and possibly LabID Event
Reporting:
Patient has surgery, is either discharged immediately (outpatient) or transferred to a unit (inpatient), is
discharged, and subsequently is readmitted with an SSI.
1. Report the infection (SSI) and attribute to the discharging (post-op) location (not the readmission
location).
2. Answer “Yes” to the MDRO infection question, if the discharging (post-op) location was following
that MDRO during the Date of Event.
3. If following LabID event reporting in the readmitting location or outpatient clinic where the
specimen was collected, report also (separately) as a LabID Event (if meets the MDRO protocol
criteria for LabID event).

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Appendix 2: Determining Patient Days for Summary Data Collection: Observation vs. Inpatients
In response to questions regarding how to count patient days for “observation” patients, the following
guidance is offered.
The NHSN instructions for recording the number of patients in an inpatient unit state that for each day of
the month selected, at the same time each day, the number of patients on the unit should be recorded. This
procedure should be followed regardless of the patient’s status as an observation patient or an inpatient.
1. Observation patients in observation locations:
An “observation” location (e.g., 24-hour observation area) is considered an outpatient unit, so time spent in
this type of unit does not ever contribute to any inpatient counts (i.e., patient days, device days, admissions).
Admissions to such outpatient units represent “encounters” for the purposes of outpatient surveillance for
LabID Event monitoring in the MDRO/CDI module.

2. Observation patients in inpatient locations:
a. If an observation patient is transferred from an observation location and admitted to an inpatient
location, then only patient days beginning with the date of admission to the inpatient location are
to be included in patient day counts (for the location or facility-wide inpatient). In this same way,
device days accrue beginning when the patient arrives in any location where device-associated
surveillance is occurring and in accordance with the location’s device-count methods.
b. If an observation patient is sent to an inpatient location, the patient should be included for all
patient and device day counts. The facility assignment of the patient as an observation patient or
an inpatient has no bearing in this instance for counting purposes, since the patient is being
housed, monitored, and cared for in an inpatient location.
Below is an example of attributing patient days to a patient admitted to an inpatient location, regardless of
whether the facility considers the patient an observation patient or an inpatient.

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MDRO and CDI Module

The examples show counts taken at: A) 12:00 am and B) 11:00 pm.
A. Count at 12:00 am (midnight):
Date
01/01

01/02
01/03
01/04
01/05

Total

Mr X Pt Day
Mr X admitted at 8:00 pm

Mr Y Pt Day
Mr Y admitted at 12:00 am

Mr X not counted because the count for
01/01/10 was taken at 12:00 am on 01/01 10
and he was not yet admitted

Mr Y is counted because the count for 01/01
was taken at 12:00 am and that is when he
was admitted

X
1
2
3
Mr X discharged at 5:00 pm
4
Counted for 01/05 because he was in the
hospital at 12:00 am on 01/05 when the
count for that day was taken
4 patient days

1
2
3
4
Mr Y discharged at 12:01 am
5
Counted for 01/05 because he was in the
hospital at 12:00 am on 01/05 when the
count for that day was taken
5 patient days

If we use the same admission dates and times for Mr. X, but a different time is selected for the patient day
count, say 11:00 pm, the total number of days in the count will be the same; they will simply be coming
from different dates.
B. Count at 11:00 pm:
Date
01/01

01/02
01/03
01/04
01/05

Mr X
Mr X admitted at 8:00 am

MR X discharged at 5:00 pm

Total

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Pt Day
Counted because the count for 01/01 is taken
at 11:00 pm on 01/01 and he is in the hospital
at that time
1
2
3
4
Not counted for 01/05 because he was not in
the hospital at 11:00 pm on 01/05 when the
count for that day was taken
X
4 patient days

MDRO and CDI Module

Determining Admission Counts for Summary Data Collection:
In response to questions regarding how to count number of admissions, the following guidance is offered.
Recognizing that there are a variety of ways in which patient day and admission counts are obtained for a
facility and for specific locations, this guidance is offered to assist with standardization within and across
facilities. It is most important that whatever method is utilized, it should be used each and every month for
consistency of data and metrics. How you operationalize this guidance will depend on how you are
obtaining the data for your counts. Any patient who meets criteria for new inclusion should be counted,
regardless of whether they are coded by the facility as an inpatient or as an observation patient. See below
for specific examples. If admissions are calculated electronically, the data must be checked to ensure that all
appropriate patients are included or excluded from those counts and that your electronic data are within +/5% of the number obtained if doing the calculations manually. If these counts are more than 5% discrepant,
then you will need to evaluate and discuss with your IT staff to determine the cause of the discrepancies and
methods to address them. The main goal is to accurately count patients in the denominators that are at risk
for potentially contributing to the numerator.
1. Facility-Wide Inpatient Admission Count: Include any new patients that are assigned to a bed in any
inpatient location within the facility regardless of billing status. Qualification as a new patient means
that the patient was not present on the previous calendar day. The daily admission counts are summed at
the end of the calendar month for a monthly facility-wide inpatient admission count.
2. Inpatient Location-Specific Admission Count: Include any new patients that are assigned to a bed in the
specific inpatient location. Qualification as a new patient means that the patient was not present on the
specific inpatient location on the previous calendar day. The daily admission counts are summed at the
end of the calendar month for a monthly inpatient location-specific admission count.

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MDRO and CDI Module

Appendix 3: Differentiating Between LabID Event and Infection Surveillance
LabID Event

Infection Surveillance (using HAI
surveillance definitions)

Protocol

LabID Event protocol in Chapter 12 of
NHSN manual

Infection Surveillance protocol in Chapter 12 of
NHSN manual and HAI site-specific definitions
in NHSN manual (e.g., BSI, UTI, SSI, PNEU,
VAE, and GI-CDI and other HAI definitions)

Signs &
Symptoms

NONE. Laboratory and admission data,
without clinical evaluation of patient

Combination of laboratory data and clinical
evaluation of patient (signs/symptoms)

Surveillance
Rules

•
•
•

HAI and POA do NOT apply
Transfer Rule does NOT apply
Location = location of patient at time
of specimen collection
Event date = specimen collection
date

•
•
•

HAI and POA do apply
Transfer Rule applies
See NHSN protocol for details regarding
location and date of event

Number of patient days and
admissions
Can be reported by specific location
or facility-wide, depending on
reporting option(s) selected
Inpatient and/or outpatient

•

Device days and patient days must be
collected separately for each monitored
location
Inpatient reporting only

Events categorized based on
inpatient or outpatient and admission
and specimen collection dates
Healthcare Facility Onset (HO) or
Community Onset (CO)
Community Onset Healthcare
Facility-Associated (CO-HCFA) for
C. difficile only
HO and CO LabID Events must be
reported to NHSN
Additional categorizations are
applied to C. difficile, which include
Incident CDI Assay and Recurrent
CDI Assay

•
•

•
Denominator
Reporting

•
•
•

Categorization
of Infections

•
•
•
•
•

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•

•

HAI protocols used
Events are either HAI or not, therefore
LabID Event categorizations do not apply
Only HAIs are reported to NHSN