Att B - Newborn Screening article

Improving and Assuring Newborn Screening
Laboratory Quality Worldwide: 30-Year Experience
at the Centers for Disease Control and Prevention
Víctor R. De Jesús, PhD, Joanne V. Mei, PhD, Carol J. Bell, BS, MT (ASCP), and
W. Harry Hannon, PhD
Newborn screening is the largest population-based genetic screening effort in the United
States. The detection of treatable, inherited congenital disorders is a major public health
responsibility. The Centers for Disease Control and Prevention’s (CDC’s) Newborn
Screening Quality Assurance Program helps newborn screening laboratories ensure that
testing accurately detects these disorders, does not delay diagnosis, minimizes falsepositive reports, and sustains high-quality performance. For over 30 years, the CDC’s
Newborn Screening Quality Assurance Program has performed this essential public health
service, ensuring the quality and accuracy of screening tests for more than 4 million infants
born each year in the United States and millions more worldwide. The Program has grown
from 1 disorder in 1978 for 31 participants to more than 50 disorders for 459 participants
in 2009. This report reviews the Program’s milestones and services to the newborn
screening community.
Semin Perinatol 34:125-133 Published by Elsevier Inc.

I

n 1961, Dr Robert Guthrie introduced the collection of
blood as dried spots on filter paper for testing newborns for
the detection of phenylketonuria (PKU).1,2 He coupled these
specially collected specimens with a unique bacterial inhibition test that he developed for measurement of phenylalanine.2 This combination of easily transportable specimens
and an inexpensive test made large-scale testing for PKU
possible. The first case of PKU detected by his procedure
occurred in a pilot study in Niagara Falls City Health Department Laboratory (New York), after 800 newborns had been
screened.1 Guthrie’s early publication, submitted in 1962,2
described his method in detail and its application to testing
blood spots obtained from newborns. It was initially rejected because another study published using his “inhibition method” had reported a high incidence of false-positive
results and had recommended not using Guthrie’s test for
PKU screening.3 Guthrie attributed the likely source of this
difference in performance to the source of the filter paper
used in the other study. Guthrie stated that the filter paper
Newborn Screening Quality Assurance Program, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease
Control and Prevention, Atlanta, GA.
Address reprint requests to Víctor R. De Jesús, PhD, The Centers for Disease
Control and Prevention, 4770 Buford Highway, NE Mail Stop F-19,
Atlanta, GA 30341. E-mail: [email protected]

0146-0005/10/$-see front matter Published by Elsevier Inc.
doi:10.1053/j.semperi.2009.12.003

used by them was not absorbent enough to allow uniform
spotting. He thought that Schleicher and Schuell Grade 903
filter paper was best suited for collection of uniform driedblood spots (DBS), and indicated some minimal criteria for
uniform performance of the filter paper.2 Because of Guthrie’s efforts, the successful introduction of DBS as a source for
PKU screening eventually led to population-based screening
of newborns nationwide using a few blood drops collected
from a heel stick and absorbed into special filter paper.
Today, newborn screening (NBS) is the largest populationbased genetic screening effort in the United States, and is
primarily performed by state public health laboratories. The
detection of treatable, inherited congenital disorders is a major public health responsibility. Screening tests are designed
to differentiate asymptomatic newborns that may have a disease from those who may not. It is important to note that
these screening tests alone are not intended to yield a diagnostic testing outcome. However, effective screening of newborns using DBS specimens collected 24-48 hours after birth
and rapid follow-up diagnostic confirmation and treatment
helps prevent mental retardation, premature death, and
other adverse outcomes. State public health laboratories or
other contracted NBS laboratories routinely screen DBS specimens for inborn errors of metabolism and other congenital
disorders that require medical intervention. The Centers for
125

126
Disease Control and Prevention’s (CDC’s) Newborn Screening Quality Assurance Program (NSQAP) helps NBS laboratories improve testing accuracy, minimize unnecessary follow-up, and establish screening reliability. For ⬎30 years,
NSQAP has performed this essential public health service,
ensuring the quality and accuracy of screening tests for ⬎4
million infants born each year in the United States. The
NSQAP is cosponsored by the Association of Public Health
Laboratories (APHL).
All NBS testing is done in a screening laboratory that meets
licensing standards specified by the Clinical Laboratory Improvement Amendments of 1988 or equivalent requirements
as determined by the Centers for Medicare and Medicaid
Services. As part of these requirements, a screening laboratory must meet certain criteria for quality control (QC). They
must also participate in proficiency testing (PT) programs
designed to evaluate the quality of laboratory performance on
a periodic basis, using specimens in the dried blood matrix
simulating the patient specimens tested. The NSQAP enables
laboratories to meet the Clinical Laboratory Improvement
Amendments quality assurance (QA) requirement for verifying test accuracy. It also provides technical guidance to participating laboratories to help assure that no screen-positive
cases are misclassified during routine screening activities.
Participation in NSQAP allows laboratories to gain testing
confidence through an external QA program that provides
comparisons of peer performance within and among methods.

Quality Assurance
Program Operations
The NSQAP provides comprehensive, multicomponent QA
services that include PT and QC services for DBS testing to
NBS laboratories, including ⬎50 newborn disorders for 459
laboratories in 63 countries. NSQAP is not just a PT program,
but a proactive, multicomponent QA program for a specialized area of public health testing. It provides external PT
specimens for voluntary comparative assessment of laboratory performance, QC materials, filter paper quality assessment, special consultations, and technical assistance to public health and private laboratories. The PT data reporting is
handled through an internet web site that permits participants to report their results online for each analyte and receive timely performance evaluation reports. It also allows
storage and retrieval of archived data-report summaries.4
All PT and QC materials should simulate, as closely as
possible, the actual specimens analyzed in the assay systems.
CDC DBS materials are certified for homogeneity, accuracy,
stability, and suitability for all NBS assays available from the
various commercial sources. Intended to supplement the
participants’ method or kit QC materials, NSQAP QC materials provide an independent external resource that allows
participants to monitor the long-term stability of commercial
assay kits. PT for the assessment of clinical laboratories dates
back to the 1940s.5,6 NSQAP provides training in the preparation of DBS materials and test methods. The program staff

V.R. De Jesús et al
also compiles and distributes 21 data reports annually for
comparative and assessment use by participants. Laboratories that report false-negative results, indicating possible
problems with their assays, are immediately contacted and
provided consultations. If problems are not identified and
corrected, laboratories would likely assume that their test
results were accurate. They would continue testing newborns
without correcting the problem, possibly missing or delaying
case diagnosis. The potential catastrophic consequences of a
delayed diagnosis underscore the need for prompt NSQAP
consultative action.
Since its inception, NSQAP has provided NBS laboratories
with quarterly panels of 5 blind-coded DBSs, and data are
now returned to the program through an internet-based, secure reporting system. Reports of individual laboratory performance and summary data by analyte and method are available within 1 week of the close of the internet data-reporting
deadline. Laboratories can retrieve their results as needed.
For PT challenges, laboratories report the cut-off value for
each analyte tested. There is a large degree of variability in
cut-off values among laboratories (Fig. 1). Participating laboratories are evaluated on the decisions that identify test results requiring additional follow-up testing (out-of-range) vs
those that do not (in-range). However, reported analytical
values are an important component of the overall grading
algorithm because specimen assessments are based on the
expected analytical values. The NSQAP grading algorithm
considers each laboratory’s reported cut-off value.7 On the
basis of qualitative results (clinical assessments) for analytes
or disorders, NSQAP summarizes annual false-positive and
false-negative rates for laboratory PT challenges. In 2008, the
false-positive rate for PT specimens was ⬍1% for all screening
analytes except decenoylcarnitinine (C10:1), a secondary
marker for medium chain acyl-CoA dehydrogenase deficiency;
immunoreactive trypsinogen (IRT), a primary marker for cystic
fibrosis (CF); and succinylacetone (data not shown), a specific
marker for tyrosinemia type 1. The false-negative rate for PT
specimens was ⬎1% for 4 of the 25 disorders or analytes monitored (tyrosine, C10, C16, and IRT) (Table 1). False-negative
errors result in immediate notification from NSQAP so that the
source of the error can be investigated, and steps can be taken to
reduce the risk of a continuously occurring error. False-positive
results are identified as a tool for the laboratory in examining
their performance metrics. A decline in the PT false-negative rate
was observed for the 6-year period from 2002 to 2008, which
confirms the value of the NSQAP in improving laboratory performance.

NSQAP: The Dried-Blood
Spot Program’s Timeline
In 1975, the Committee for the Study of Inborn Errors of
Metabolism, National Academy of Sciences, noted that better
QC of PKU screening was vital, and recommended that a
single laboratory within the CDC be responsible for maintaining the proficiency of the regional laboratories testing
newborns.8 In the late 1970s, NSQAP began its critical work

Newborn screening laboratory quality

Figure 1 Cutoff ranges for selected analytes showing harmonization across time. (A) Thyroid-stimulating hormone
(TSH), (B) Leucine (Leu), (C) Octanoylcarnitine (C8).

127

V.R. De Jesús et al

128
Table 1 Domestic False-Negative Rates (%) for 2003-2008
Year
Disorder/Analyte

2003

2004

2005

2006

2007

2008

Average 6-year
False-Negative Rate

Phenylketonuria (phenylalanine)
Maple syrup urine disease (leucine)
Homocystinuria (methionine)
Maple syrup urine disease (valine)
Tyrosinemia I, II, III (tyrosine)
Citrullinemia (citrulline)
C3 Screen
C4 Screen
C5 Screen
C5DC Screen
C6 Screen
C8 Screen
C10 Screen
C14 Screen
C16 Screen
Hypothyroidism
Congenital adrenal hyperplasia
Galactosemia
Biotinidase deficiency
Galactosemia
Cystic fibrosis (IRT)

0
0.8
0
1.8
5.7
2.3
0
0
0
0
0
0
0
0
10.5
0
0.7
0
0
0
1.5

0
0
0
0
2.9
0
1
1.2
1.2
0
0
0.7
4.0
1.4
2.4
0
0.5
1.5
0
0.5
1.1

0.8
0
1.4
0
0
0
0
0
1.7
0
0
0.6
1.1
1.1
0
0.6
2.4
2.2
0.6
0
0

0.6
0
0
0
1.6
0
1.9
0.4
0.8
3.7
0
0.6
1.3
0.7
0.6
0
0.5
0
0
0
2.1

0
0
0
0
0.7
0
0
0
0
0
0.6
0
0
0
0
0.5
0
1.1
0.8
0
1.6

1.1
0
0
0
3.3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1.3

0.4
0.1
0.2
0.3
2.4
0.4
0.5
0.3
0.6
0.6
0.1
0.3
1.1
0.5
2.3
0.2
0.7
0.8
0.2
0.1
1.3

with 10 state public health laboratories testing for 1 disorder,
congenital hypothyroidism.
The expansion of NSQAP services to NBS laboratories began in 1978, when the Health Resources and Services Administration (HRSA) provided funds to launch the program and
became its sponsor. NSQAP distributed the first thyroxine
and thyroid-stimulating hormone QC materials in DBS that
year, after a 1-year pilot study to create DBS QC materials for
congenital hypothyroidism screening (Table 2). In January
1979, Dr Guthrie sent a letter to CDC encouraging and supporting expansion of the program to provide DBS materials
for more disorders, including PKU. The first PT survey for
PKU occurred in 1980, followed by distribution of QC materials for phenylalanine in 1983. That same year, the NSQAP

Table 2 Timeline for the Addition of Disorders to NSQAP
1978
1980
1988
1990
1991
1992
1995
1997
2000
2002
2005
2006
2007
2008
2009

Congenital hypothyroidism
Phenylketonuria
Galactosemia, HIV seroprevalence
Congenital adrenal hyperplasia
Sickle cell disorders
Maple syrup urine disease
Homocystinuria
Biotinidase
Fatty acid and organic acid disorders
Cystic fibrosis/IRT, diabetes type 1
Toxoplasmosis
2nd Tier congenital adrenal hyperplasia
Cystic fibrosis DNA mutation panel
Succinylacetone, lysosomal storage disorders
2nd Tier maple syrup urine disease

Filter Paper Evaluation Project was established in response to
complaints about filter paper reliability and reproducibility.
NBS filter paper quality was assessed using a DBS-based
quantitative radioisotopic test to measure and monitor filter
paper performance characteristics under a standardized protocol. This project ultimately resulted in the creation of a
national standard for blood collection on filter paper. Initially, a product of the National Committee for Clinical Laboratory Standards , the standard is now in its fifth edition as
a product of the Clinical and Laboratory Standards Institute
(CLSI). The standard (CLSI LA4-A5) addresses issues associated with specimen collection, the filter paper collection device, and the transfer of blood onto filter paper.9 On the basis
of sustained compliance with the performance parameters
specified in LA4-A5, the Food and Drug Administration
(FDA) has currently registered 2 commercial sources of filter
paper for blood collection.
In 1988, NSQAP distributed the first galactosemia PT survey and its first infectious disease DBS materials. Human
immunodeficiency virus type 1 (HIV-1) DBS QC materials
and PT challenges were created as part of a seroprevalence
survey among childbearing women.10 The first galactose QC
materials were distributed in 1989. That same year, NSQAP
celebrated its 10th anniversary with an enrollment of 75 laboratories in 4 countries, and offered QA materials for 8 disorders and 5 analytes.
The first congenital adrenal hyperplasia (CAH) PT survey,
using 17-␣-hydroxyprogesterone, was conducted in 1990,
and in 1991, the first CAH QC materials were distributed to
program participants worldwide. Another program milestone was achieved in 1991, when identification of sickle cell

Newborn screening laboratory quality
disease and other hemoglobinopathies was added to the QA
program. Inclusion of these conditions in NBS had been recommended after the results of research that indicated that
pneumococcal sepsis in young children with sickle cell anemia was reduced by as much as 84% through early identification and treatment.11
NSQAP has had a long-standing relationship with the
APHL dating to the program’s initiation in 1978. A Memorandum of Understanding was formally signed in October
1992, which produced formal sponsorship and paved the
way for the establishment of an APHL QA/QC/PT Subcommittee. The Subcommittee is charged with advising NSQAP
on its NBS-related activities and the needs of the public
health community. The QA/QC subcommittee comprises
representative members from state public health laboratories
across the country.
In 1994, NSQAP achieved another major milestone by
establishing a QA program for DNA confirmation, using DBS
specimens for hemoglobins A, S, C, E, and D. This work was
initiated using HRSA start-up funds, and allowed NSQAP to
expand into DNA testing, as technology became available in
screening and diagnostic laboratories. NSQAPs non-DNA expansion continued in 1995, with PT survey for homocystinuria, and made available QC materials for methionine. Building on earlier success with its hemoglobins program, DNA
testing for CF was established at the NSQAP laboratory in
1997. The CF DNA program coincided with the publication
of the proceedings of a January 1997 workshop that discussed the benefits and risks associated with NBS for CF, and
developed public health policy concerning such screening.12
Additionally, in 1997, the first biotinidase deficiency PT survey was initiated, bringing the total to 17 disorders and 13
analytes covered by NSQAP. In 1998, NSQAP celebrated its
20th anniversary of service to NBS laboratories in the United
States and 33 other countries by providing DBS QA materials
to 198 laboratories, including 163 QC and 151 PT participants. However, after nearly 20 years of support, HRSA
ended its NSQAP funding and sponsorship.
The introduction of tandem mass spectrometry (MS/MS)
as a viable technique for detecting phenylalanine in DBS,13
revolutionized the practice of NBS for metabolic disorders.
Recognizing the need for best practices guidelines for MS/MS
use in NBS Laboratories, the National Newborn Screening
and Genetics Resource Center, in collaboration with NSQAP/
CDC and HRSA, convened a workshop in June 2000, attended by approximately 50 participants from public and
private health agencies and universities. Workshop participants examined concerns about integrating MS/MS technology into ongoing NBS activities, and published a report14 to
assist policymakers, program managers, and laboratorians in
informed decision making. In 2001, the NSQAP launched a
pilot PT survey for laboratories testing DBS by MS/MS for
amino acid, fatty acid oxidation, and organic acid disorders.
In 2002, NSQAP brought MS/MS detectable analytes into PT
evaluation status, using cutoff decisions and presumptive
case classifications for participant grading. Additionally, the
program began distributing the first galactose-1-phosphate
uridyl transferase PT survey and specimens for IRT. In 2003,

129
NSQAP offered the first PT survey for DNA confirmatory testing
for CF. The program’s expansion continued in 2005, when a
pilot PT survey for Toxoplasma gondii antibodies was launched
for laboratories performing toxoplasmosis screening.
Acquisitions of MS/MS technology by NBS laboratories in
early 2000, presented a unique challenge to incorporate
MS/MS into NBS. With this new technology and its multianalyte capability, NBS programs could now detect several
disease biomarkers simultaneously from a single specimen
aliquot. Additionally, an increased potential for second-tier
testing to improve specificity of traditional screening tests
was now available. The American College of Medical Genetics (ACMG), because of a HRSA contract, recommended a
uniform panel of conditions for inclusion by all state NBS
programs.15 The expert working group recommended 54
conditions (29 core conditions—including hearing screening—and 25 secondary targets) for implementation in all
state NBS programs. This “uniform panel” was subsequently
endorsed by the Secretary of Health’s Advisory Committee on
Heritable Disorders and Genetic Diseases in Newborns and
Children. To date, all states have expanded to include at least
the core biochemical tests. NSQAP initiated and continuously expanded its coverage of MS/MS detected analytes in its
QA services; all analytes were identified in the uniform panel.
In 2006, NSQAP launched a CAH PT pilot survey in support
of laboratories evaluating second tier MS/MS-based CAH
testing.16 This procedure involves detecting secondary steroid markers and establishing a clinical algorithm for identification of CAH-affected newborns.
In 2007, NSQAP expanded its DNA mutation panel for CF
PT surveys. Mutations were added to the IRT PT program,
thereby providing CF screening laboratories with QA materials for primary and secondary CF assays. This enhanced the
NSQAPs expertise in molecular biology-based technology,
while establishing a solid foundation to assist participating
laboratories with their DNA-based screening assays. NSQAP
celebrated its 30th anniversary in 2008 by launching a PT
survey for succinylacetone, a specific marker for tyrosinemia
type 1,17,18 and a pilot program for lysosomal storage disorders detected by MS/MS,19,20 in collaboration with the Newborn Screening Translation Research Initiative at CDC. Currently, the total number of laboratories and countries served
by NSQAP for all facets of the program are 547 laboratories in
78 countries (Table 3), covering over 50 disorders and 48
analytes (Table 4). The NSQAP coverage by the end of 2009
will include 52 of the 54 analytes in the ACMG uniform panel
and 2 infectious diseases not in this panel, in addition to
other analytes currently used in pilot studies for possible
inclusion in the uniform panel, for example, severe congenital immunodeficiencies. NSQAP annually produces approximately a million DBS to meet the QA and PT needs of its
participating laboratories worldwide.

Filter Paper (Blood Collection
Device) Quality Assurance
Beginning with Guthrie’s report in 1963,2 the special filter
paper matrix for blood collection for NBS has periodically

V.R. De Jesús et al

130
Table 3 Participating Countries in the Newborn Screening
Quality Assurance Program (N ⴝ 78a)
Argentina
Armenia
Australia
Austria
Belgium
Brazil
Cambodia
Canada
Chile
China
Colombia
Costa Rica
Cote d’Ivoire
Cuba
Czech Republic
Denmark
Dominican Republic
Egypt
Estonia
Ethiopia
Finland
France
Germany
Greece
Guatemala
Haiti

Hungary
Iceland
India
Ireland
Israel
Italyb
Japan
Kazakhstan
Kenya
Kyrgyzstan
Latvia
Lebanon
Lithuania
Luxembourg
Malaysia
Malawi
Mexico
Netherlands
New Zealand
Nicaragua
Norway
Pakistan
Panama
Peru
Philippines
Poland

Portugal
Russia
Saudi Arabia
Senegal
Singapore
Slovak Republic
South Africa
South Korea
Spain
Sweden
Switzerland
Tajikistan
Taiwan
Tanzania
Thailand
Turkey
Uganda
Ukraine
United Arab Emirates
United Kingdom
United States
Uruguay
Uzbekistan
Venezuela
Vietnam
Zambia

aIncludes

laboratories receiving DBS services for HIV antibodies
and lysosomal storage disorders.
bFirst international participant (May 1978).

created analytical performance issues. As a vital service to the
NBS community, NSQAP evaluates NBS filter paper’s absorption characteristics and other parameters for all manufactured lots of filter papers from manufacturers with FDA clearance (approval). According to a mutual voluntary agreement,
the filter paper manufacturer provides NSQAP with statistically valid sample sets from different reels of the unprinted
filter paper production lot for evaluation, using NSQAPs

standardized procedures.9 The manufacturer has the responsibility for establishing its own parallel evaluation laboratory.
NSQAP’s evaluation results are provided for comparison
with those of the primary evaluator. Agreement is achieved
between the 2 evaluation sources before a new production lot
of filter paper is released for printing and distribution.
DBS collection requires the use of special grades of commercially manufactured paper, as a unique whole blood collection matrix for NBS and other related applications. Because the paper punch is a volumetric measurement for an
analytical method, a high degree of uniformity is essential to
minimize variance from the lot-to-lot filter paper transitions
for specimens, calibrators, QC materials, and unknown samples.9 In the Unites States, only papers from sources cleared
by the FDA are acceptable for blood collection for NBS tests.
Critical to proper and effective use of this matrix is an ongoing assessment and evaluation of new production lots as they
are manufactured, as well as the monitoring of problems
identified with individual lots in use by NBS programs.
NSQAP’s evaluation parameters were established in 1980,
with voluntary cooperation from the manufacturer of Grade
903 paper. Figure 2 shows the results from NSQAP’s evaluation of Grade 903 paper for 30 years. Lysed red blood cells
were originally used for the evaluations to control for heterogeneity due to cell lysis; but for the last 20 years, both lysed
and intact red blood cell preparations have been used for
these evaluations. The 2 methods serve as a cross check for
performance comparison. Figure 2 shows that 3 lots of paper
were outside the expected performance criteria in 1981, and
this created great concern for the testing community until the
manufacturer re-established the performance quality of the
paper. This event firmly established the need for continued
monitoring of the filter paper before its distribution.
NSQAP chose to monitor the following parameters: absorption volume, absorption time, physical appearance, and
homogeneity, to ensure consistency among production lots,
before a new lot is distributed to the user community. From
earlier studies, NSQAP established a working protocol, a QC

Table 4 List of Biomarkers Covered by NSQAP (2009)
Biotinidase
Thyroxine
Thyroid-stimulating hormone
17 ␣-Hydroxyprogesterone
Total galactose
Uridyltransferase (GALT)
Citrulline
Phenylalanine
Leucine
Valine
Methionine
Arginine
Tyrosine
Succinylacetone
␣-Glucosidase (GAA)
␤-Galactosidase (GALC)

Free Carnitine (C0 low)
Propionylcarnitine (C3)
Malonylcarnitine (C3DC)
Isobutyrylcarnitine (C4)
3-Hydroxybutyrylcarnitine (C4OH)
Isovalerylcarnitine (C5)
Glutarylcarnitine (C5DC)
3-Hydroxyisovalerylcarnitine
(C5OH)
Tiglylcarnitine (C5:1)
Hexanoylcarnitine (C6)
Octanoylcarnitine (C8)
Decanoylcarnitine (C10)
Decenoylcarnitine (C10:1)
Myristoylcarnitine (C14)
␣ -Galactosidase (GLA)
Acid ␤-Glucocerebrosidase (ABG)

Tetradecenoylcarnitine (C14:1)
3-Hydroxypalmitoylcarnitine (C16OH)
Palmitoylcarnitine (C16)
Immunoreactive trypsinogen (IRT)
CF DNA Mutation Panel
Hemoglobinopathies
SS, SC, SD, SE mutations
Diabetes Type 1 risk mutations
Toxoplasmosis (IgG, IgM)
HIV type 1 antibodies
Creatine kinase (DMD)
Androstenedione
Cortisol
11-Deoxycortisol
21-Deoxycortisol
Acid sphingomyelinase (ASM)

Newborn screening laboratory quality

131

Figure 2 Evaluation of Grade 903 Blood Collection Filter Paper: 1978-2009.

system for evaluation, and the set of parameters and performance expectations to monitor for criteria adherence on a
routine basis. This protocol became a part of the CLSI’s Approved Standard in 1982. NSQAP has applied this protocol
for troubleshooting filter paper problems, evaluating new
production lots, and assessing proposed products from new
manufacturers for almost 30 years.

Future Directions
Infectious Diseases Testing and
Surveillance Using Dried Blood Spots
Infectious disease testing in the United States has used newborn DBSs to estimate the seroprevalence of HIV in childbearing women10 and to screen newborns for T. gondii exposure.21 These assays detect specific antibodies made against
the infectious agents. The NSQAP played a lead role in assuring the quality of testing for the national HIV seroprevalance
survey of childbearing women for 10 years, and continues to
provide QA materials and services for laboratories using DBS
for HIV screening. QA services for toxoplasmosis testing were
introduced in 2005, although only a few programs in the
United States included this test in their screening panel. Additionally, NBS for congenital cytomegalovirus infection,
which is a leading cause of sensorineural hearing loss and
developmental disability in children, has been proposed for

Unites States hospitals and public heath programs.22 NSQAP
has implemented research efforts into the development of
DBS QA materials for cytomegalovirus screening.

Role of Technologies in Newborn Screening
DBS technologies for NBS have evolved over time, and now
encompass all clinical platforms from bacterial inhibition assays to many types of immunochemical assays to multiplexed
methods, such as MS/MS, multimarker high performance
liquid chromatography testing for hemoglobinopathies, and
multianalyte immunoassays for HIV antibodies, hepatitis C
antibodies, and hepatitis B antigens23,24 to polymerase chain
reaction. The NSQAP stays current with technological advances and plans for development of QA materials and
services that will best meet requirements for the newly
developed measurement systems, for example, lab-on-achip technologies.25
NBS activities have conventionally been influenced by
emerging technologies, and NSQAP strives to stay in the
forefront of technological and scientific developments to improve its role in providing QA services to NBS Laboratories.
The program now works closely with a select group of molecular biologists, who have expertise in understanding how
genetics and changes in DNA are associated with important
public health issues, such as diabetes, kidney disease, birth
defects, and asthma. Many NBS laboratories either use or are

V.R. De Jesús et al

132
considering the addition of DNA-based testing as second-tier
testing to confirm positive screening results or enhance specificity of testing for disorders in the ACMG uniform panel (eg,
galactosemia, CAH). Second-tier DNA-based testing is currently used by most state public health screening programs
for CF screening,26 as well as in confirmatory testing of
Krabbe disease in New York State.27 As a result, NSQAP is
building on its CF QA program to create, certify, and distribute DBS materials that laboratories can use, to ensure that
these DNA tests meet technical proficiency goals.
In addition to the goal to increase QA services for DNAbased tests, NSQAP aims to expand the availability of DBS
QA materials for all the core and secondary target conditions
listed by the ACMG report.15 The increased availability of
commercial and academic synthetic sources of many of the
acylcarnitine compounds has enabled NSQAP to acquire and
incorporate them into its DBS production schedule. In 2010,
the program will offer DBS QC and PT materials for 27 of
the 28 core disorders that are tested using DBS (excludes
hemoglobin S/␤-thalassemia) and for 24 of the 25 secondary target disorders (excludes 2,4-dienoyl-CoA reductase
deficiency); when source materials are located, these remaining 2 markers will be added in the near future. The latest
additions to NSQAP panels include 3-hydroxypalmitoylcarnitine (C16OH), 3-hydroxybutyrylcarnitine (C4OH), tiglylcarnitine (C5: 1), and arginine, which are primary markers for longchain L-3-hydroxyacyl-CoA-dehydrogenase deficiency, medium/
short chain acyl-CoA-dehydrogenase deficiency, ␤-ketothiolase
deficiency, and argininemia, respectively. NSQAP will continuously focus on achieving the QA needs for all analytes detected
in NBS for disorders identified in recommended panels and
those in pilot testing programs.
The Newborn Screening Saves Lives Act, which was signed
into law in 2008,28 indirectly provided support to secure a
funding source for the NSQAP that resulted in improved
technology resources and increased staff, and other capabilities to better serve the NBS public health community. The
bill identifies CDC’s role under “Laboratory Quality” while
endorsing and expanding the activities of NSQAP to respond
to the QA needs for NBS laboratories. Furthermore, additional monies were obtained to fund grants for state pilot
studies for severe congenital immunodeficiencies disorders
and for development of second-tier tests for enhanced specificity in state programs. This legislative bill also required the
development of a national contingency plan for NBS, which
is to be used by states, regions, or consortia of states in the
event of a public health emergency. In 2008, a planning
meeting of stakeholders was held at CDC in collaboration
with HRSA, and a report of the group’s recommendations is
expected to be issued in late 2009. As part of these efforts for
contingency planning, APHLs QA/QC NBS Subcommittee
developed a generic NBS collection card for use in emergency
situations. The blood collection cards have been printed and
are housed at CDC. NSQAP will be responsible for assuring
the continuous performance of the blood collection filter paper during storage. Request for the emergency cards will be
made through the APHL office.

Conclusions
The NSQAP with its many facets is designed to help screening laboratories achieve excellent technical proficiency and
maintain confidence in their performance while processing
large volumes of specimens daily. The program continually
strives to produce certified DBS materials for reference and
QC analysis, to improve the quality and scope of services, and
to provide immediate consultative and technical assistance.
Over 10 million DBS QA materials have been distributed
globally during 30 years of operation. Through NSQAPs interactive efforts with the program’s participants, it aspires to
meet their growing and changing NBS needs, always with an
eye on future technological advances. The accuracy of screening tests marks the difference between life and death for
many infants; in other instances, identifying newborns with a
disorder means that they can be treated, and thus avoid lifelong disability or cognitive impairment. Thousands of newborns and their immediate families have benefited from reliable and accurate testing that has been accomplished by a
network of screening laboratories and the NSQAP.

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