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Central Line-Associated Bloodstream Infection (CLABSI) Event
Introduction: An estimated 248,000 bloodstream infections occur in U.S. hospitals each
year1, and a large proportion of these are associated with the presence of a central
vascular catheter. For the purposes of NHSN, such infections are termed central lineassociated bloodstream infections (CLABSI). Bloodstream infections are usually serious
infections typically causing a prolongation of hospital stay and increased cost and risk of
mortality.
CLABSI can be prevented through proper management of the central line. These
techniques are addressed in the CDC’s Healthcare Infection Control Practices Advisory
Committee (CDC/HIPAC) Guidelines for the Prevention of Intravascular CatheterRelated Infections, 2011.2
Settings: 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), neonatal units including neonatal intensive care units (NICUs), stepdown units,
wards, and long term care units. A complete listing of inpatient locations can be found in
Chapter 15.
NOTE: Surveillance for CLABSIs after the patient is discharged from the facility is not
required, however, if discovered, these infections should be reported to NHSN. No
additional central line days are reported.
Requirements: Surveillance for CLABSI in at least one inpatient location in the
healthcare institution for at least one calendar month as indicated in the Patient Safety
Monthly Reporting Plan (CDC 57.106).
Definitions: As for all infections reported to NHSN, infections associated with
complications or extensions of infections already present on admission, unless a change
in pathogen or symptoms strongly suggests the acquisition of a new infection, are not
considered healthcare associated. Therefore, infections that become apparent within the
first few days of admission must be carefully reviewed to determine whether they should
be considered healthcare associated.
Primary bloodstream infections (BSI) are laboratory-confirmed bloodstream infections
(LCBI) that are not secondary to an HAI meeting CDC/NHSN criteria at another body
site (see criteria in Chapter 17 or a community-associated infection.) Report BSIs that
are central line associated (i.e., a central line or umbilical catheter was in place at the time
of, or within 48 hours before, onset of the event).
NOTE: There is no minimum period of time that the central line must be in place in order
for the BSI to be considered central line associated.

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Location of attribution: The inpatient location where the patient was assigned on the date
of the BSI event, which is further defined as the date when the first clinical evidence
appeared or the date the specimen used to meet the BSI criteria was collected, whichever
came first.
EXAMPLE: Patient who had no clinical signs or symptoms of sepsis upon arrival to the
Emergency Department, has a central line inserted there before being admitted to the
MICU has a central line inserted in the Emergency Department and then is admitted to
the MICU. Within 24 hours of admission to the MICU, patient meets criteria for BSI.
This is reported to NHSN as a CLABSI for the MICU, because the Emergency
Department is not an inpatient location and no denominator data are collected there.
TRANSFER RULE EXCEPTION: If a CLABSI develops within 48 hours of transfer
from one inpatient location to another in the same facility, or a new facility, the infection
is attributed to the transferring location. This is called the Transfer Rule and examples
are shown below:
Patient with a central line in place in the SICU is transferred to the surgical ward.
Thirty six (36) hours later, the patient meets the criteria for BSI. This is reported
to NHSN as a CLABSI for the SICU.
Patient is transferred to the medical ward from the MSICU after having the
central line removed. Within 24 hours, patient meets criteria for a BSI. This is
reported to NHSN as a CLABSI for the MSICU.
Patient with a central line in place is transferred from the medical ward to the
coronary care ICU (CCU). After 4 days in the CCU, the patient meets the criteria
for a BSI. This is reported to NHSN as a CLABSI for the CCU.
Patient on the urology ward of Hospital A had the central line removed and is
discharged home a few hours later. The IP from Hospital B calls the next day to
report that this patient has been admitted to Hospital B with a BSI. This CLABSI
should be reported to NHSN for, and by, Hospital A and attributed to the urology
ward. No additional catheter days are reported.
Central line: An intravascular catheter that terminates at or close to the heart or in one of
the great vessels which is used for infusion, withdrawal of blood, or hemodynamic
monitoring. The following are considered great vessels for the purpose of reporting
central-line BSI and counting central-line days in the NHSN system: Aorta, pulmonary
artery, superior vena cava, inferior vena cava, brachiocephalic veins, internal jugular
veins, subclavian veins, external iliac veins, common iliac veins, femoral veins, and in
neonates, the umbilical artery/vein.
NOTES:
1. Neither the insertion site nor the type of device may be used to determine if a line
qualifies as a central line. The device must terminate in one of these vessels or in
or near the heart to qualify as a central line.
2. An introducer is considered an intravascular catheter, and depending on the
location of its tip, may be a central line.

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3. Pacemaker wires and other nonlumened devices inserted into central blood
vessels or the heart are not considered central lines, because fluids are not infused,
pushed, nor withdrawn through such devices.
4. The following devices are not considered central lines: extracorporeal membrane
oxygenation (ECMO), femoral arterial catheters and Intraaortic balloon pump
(IABP) devices. If you have a question about whether a device qualifies as a
central line, please email us at [email protected].
Infusion: The introduction of a solution through a blood vessel via a catheter lumen. This
may include continuous infusions such as nutritional fluids or medications, or it may
include intermittent infusions such as flushes or IV antimicrobial administration, or
blood, in the case of transfusion or hemodialysis.
Umbilical catheter: A central vascular device inserted through the umbilical artery or vein
in a neonate.
Temporary central line: A non-tunneled catheter.
Permanent central line: Includes
o Tunneled catheters, including certain dialysis catheters
o Implanted catheters (including ports)
Laboratory-confirmed bloodstream infection (LCBI): Must meet one of the
following criteria:
Criterion 1: Patient has a recognized pathogen cultured from one or more blood
cultures
and
organism cultured from blood is not related to an infection at another site. (See Notes 1
and 2 below.)
Criterion 2: Patient has at least one of the following signs or symptoms: fever
(>38oC), chills, or hypotension
and
signs and symptoms and positive laboratory results are not related to an infection at
another site
and
common commensal (i.e., diphtheroids [Corynebacterium spp. not C. diphtheriae],
Bacillus spp. [not B. anthracis] , Propionibacterium spp., coagulase-negative
staphylococci [including S. epidermidis], viridans group streptococci, Aerococcus spp.,
Micrococcus spp.) is cultured from two or more blood cultures drawn on separate
occasions.
Criterion 3: Patient < 1 year of age has at least one of the following signs or
symptoms: fever (>38oC core) hypothermia (<36oC core), apnea, or bradycardia
and
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signs and symptoms and positive laboratory results are not related to an infection at
another site
and
common skin commensal (i.e., diphtheroids [Corynebacterium spp. not C. diphtheriae],
Bacillus spp. [not B.anthracis], Propionibacterium spp., coagulase-negative
staphylococci [including S. epidermidis], viridans group streptococci, Aerococcus spp.,
Micrococcus spp.) is cultured from two or more blood cultures drawn on separate
occasions. (See Notes 3, 4 and 5 below.)
NOTES:
1.
In criterion 1, the phrase “one or more blood cultures” means that at least one
bottle from a blood draw is reported by the laboratory as having grown organisms
(i.e., is a positive blood culture).
2.
In criterion 1, the term “recognized pathogen” does not include organisms
considered common commensals (see criteria 2 and 3 for a list of common
commensals). A few of the recognized pathogens are S. aureus, Enterococcus
spp., E. coli, Pseudomonas spp., Klebsiella spp., Candida spp., etc.
3.
In criteria 2 and 3, the phrase “two or more blood cultures drawn on separate
occasions” means 1) that blood from at least two blood draws were collected
within two days of each other (e.g., blood draws on Monday and Tuesday or
Monday and Wednesday would be acceptable for blood cultures drawn on
separate occasions, but blood draws on Monday and Thursday would be too far
apart in time to meet this criterion), and 2) that at least one bottle from each blood
draw is reported by the laboratory as having grown the same common commensal
(i.e., is a positive blood culture). (See Note 4 for determining sameness of
organisms.)
a. For example, an adult patient has blood drawn at 8 a.m. and again at 8:15 a.m.
of the same day. Blood from each blood draw is inoculated into two bottles
and incubated (four bottles total). If one bottle from each blood draw set is
positive for coagulase-negative staphylococci, this part of the criterion is met.
b. For example, a neonate has blood drawn for culture on Tuesday and again on
Saturday and both grow the same common commensal. Because the time
between these blood cultures exceeds the two-day period for blood draws
stipulated in criteria 2 and 3, this part of the criteria is not met.
c. A blood culture may consist of a single bottle for a pediatric blood draw due
to volume constraints. Therefore, to meet this part of the criterion, each bottle
from two or more draws would have to be culture-positive for the same
commensal.
4.
If the common commensal is identified to the species level from one culture, and
a companion culture is identified with only a descriptive name (e.g., to the genus
level), then it is assumed that the organisms are the same. The organism
identified to the species level should be reported as the infecting pathogen along
with its antibiogram if available (see Table 1 below).

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Table 1. Examples of how to report speciated and unspeciated common commensals
Culture Report
Companion
Report as…
Culture Report
S. epidermidis
CoagulaseS. epidermidis
negative
staphylococci
Bacillus spp. (not anthracis)
B. cereus
B. cereus
Strep viridans
S. salivarius
S. salivarius
5.

6.
7.

Only genus and species identification should be utilized to determine the
sameness of organisms. No additional comparative methods should be used (e.g.,
morphology or antibiograms) because laboratory testing capabilities and protocols
may vary between facilities. This will reduce reporting variability, solely due to
laboratory practice, between facilities reporting LCBIs meeting criterion 2.
Report the organism to the genus/species level only once, and if antibiogram data
are available, report the results from the most resistant panel.
LCBI criteria 1 and 2 may be used for patients of any age, including patients < 1
year of age.
Specimen Collection Considerations:
Ideally, blood specimens for culture should be obtained from two to four blood
draws from separate venipuncture sites (e.g., right and left antecubital veins), not
through a vascular catheter. These blood draws should be performed
simultaneously or over a short period of time (i.e., within a few hours).3,4 If your
facility does not currently obtain specimens using this technique, you must still
report BSIs using the criteria and notes above, but you should work with
appropriate personnel to facilitate better specimen collection practices for blood
cultures.

REPORTING INSTRUCTIONS:
Report organisms cultured from blood as BSI – LCBI when no other site of infection
is evident.
When there is a positive blood culture and clinical signs or symptoms of localized
infection at a vascular access site, but no other infection can be found, the infection is
considered a primary BSI.
Purulent phlebitis confirmed with a positive semiquantitative culture of a catheter tip,
but with either negative or no blood culture is considered a CVS-VASC, not a BSI
nor an SST-SKIN or ST infection.
Occasionally a patient with both peripheral and central IV lines develops a primary
bloodstream infection (LCBI) that can clearly be attributed to the peripheral line (e.g.,
pus at the insertion site and matching pathogen from pus and blood). In this situation,
enter “Central Line = No” in the NHSN application. You should, however, include
the patient’s central line days in the summary denominator count.

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Numerator Data: The Primary Bloodstream Infection (BSI) form (CDC 57.108) is used
to collect and report each CLABSI that is identified during the month selected for
surveillance. The Instructions for Completion of Primary Bloodstream Infection Form
(Tables of Instructions, Tables 2 and 2a.) contains brief instructions for collection and
entry of each data element on the form. The Primary BSI form includes patient
demographic information and whether a central line was present, and, if so, the type of
central line the patient had as appropriate to the location; these data will be used to
calculate line-specific infection rates. Additional data include the specific criteria met for
identifying the primary BSI, whether the patient died, the organisms isolated from blood
cultures, and the organisms’ antimicrobial susceptibilities.
Denominator Data: Device days and patient days are used for denominators (see
Chapter 16, Key Terms). Device-day denominator data that are collected differ
according to the location of the patients being monitored; however, they should be
collected at the same time each day. When denominator data are available from electronic
databases, these sources may be used as long as the counts are not substantially different
(+/- 5%) from manually-collected counts.
For ICUs and locations other than specialty care areas (SCAs) and NICUs, the number of
patients with one or more central lines of any type is collected daily, at the same time
each day, during the month and recorded on the Denominators for Intensive Care Unit
(ICU)/Other Locations (Not NICU or Specialty Care Area (SCA)) (CDC 57.118). Only
the totals for the month are entered into NHSN. When denominator data are available
from electronic sources (e.g., central line days from electronic charting), these sources
may be used as long as the counts are not substantially different (+/- 5%) from manuallycollected counts.
For specialty care areas, the number of patients with one or more central lines is
dichotomized into those with permanent central lines and those with temporary central
lines on the Denominators for Specialty Care Area (CDC 57.117) form. Each is
collected daily, at the same time each day. Only the total for the month are entered into
NHSN. This distinction in lines is made because permanent lines are commonly used in
patients frequenting these areas and may have lower rates of associated infection than
central lines inserted for temporary use. If a patient has both a temporary and a
permanent central line, count the day only as a temporary line day. The Instructions for
Completion of Denominators for Intensive Care Unit (ICU)/Other Locations Form
(Tables of Instructions, Table 6) and Instructions for Completion of Denominators for
Specialty Care Areas (SCA) Form (Tables of Instructions, Table 7) contain brief
instructions for collection and entry of each data element on the forms.
In NICUs, again because of differing infection risks, the number of patients with central
lines and those with umbilical catheters is collected daily, at the same time each day,
during the month. If a patient has both an umbilical catheter and a central line, count the
day only as an umbilical catheter day. On the Denominators for Neonatal Intensive Care

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Unit (NICU) (CDC 57.116) form, patients are further stratified by birthweight in five
categories since risk of BSI also varies by birthweight.
NOTE: The weight of the infant at the time of BSI is not used and should not be
reported. For example, if a neonate weighs 1006 grams at birth but remains in the NICU
for two months and has a body weight of 1650 grams when it develops a CLABSI, record
the birthweight of 1006 grams on the BSI form. The Instructions for Completion of
Denominators for Neonatal Intensive Care Unit (NICU) form (Tables of Instructions,
Table 8) contains brief instructions for collection and entry of each data element on the
forms.
Data Analyses: The SIR is calculated by dividing the number of observed infections by
the number of expected infections. The number of expected infections, in the context of
statistical prediction, is calculated using CLABSI rates from a standard population during
a baseline time period as reported in the NHSN Report.
NOTE: The SIR will be calculated only if the number of expected HAIs (numExp) is
≥ 1.

While the CLABSI SIR can be calculated for single locations, the measure also allows
you to summarize your data across multiple locations, adjusting for differences in the
incidence of infection among the location types. For example, you will be able to obtain
one CLABSI SIR adjusting for all locations reported. Similarly, you can obtain one
CLABSI SIR for all specialty care areas in your facility.
The CLABSI rate per 1000 central line days is calculated by dividing the number of
CLABSI by the number of central line days and multiplying the result by 1000. The
Central Line Utilization Ratio is calculated by dividing the number of central line days by
the number of patient days. These calculations will be performed separately for different
types of ICUs, specialty care areas, and other locations in the institution. Separate rates
and ratios will also be calculated for different types of catheters in specialty care areas
and NICUs, and for birthweight categories in NICUs.
1

Klevens RM, Edward JR, et al. Estimating health care-associated infections and deaths in U.S. hospitals,
2002. Public Health Reports 2007;122:160-166.

2

O’Grady NP, Alexander M, Burns LA,, Dellinger EP, Garland J, Heard SO, Maki DG, et al. Guidelines
for the prevention of intravascular catheter-related infections, 2011. Clinical Infectious Diseases 2011; 52
(a):1087-99.

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3

Clinical and Laboratory Standards Institute (CLSI). Principles and Procedures for Blood Cultures;
Approved Guideline. CLSI document M47-A (ISBN 1-56238-641-7). Clinical and Laboratory Standards
Institute, 940 West Valley Road, Suite 1400, Wayne, Pennsylvania, USA, 2007.
4

Baron EJ, Weinstein MP, Dunne Jr WM, Yagupsky P, Welch DF, and Wilson DM. Blood Cultures IV.
ASM Press: Washington, DC; 2005.

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