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Indian Pediatr 2019;56: 275-276 |
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Newborn Screening for Congenital
Hypothyroidism in India: Let’s Just Do It!
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Bradford L. Therrell, Jr.
From the University of Texas Health Science Center,
San Antonio; and US National Newborn Screening and Genetics Resource
Center, Austin; Texas, USA.
Email: [email protected]
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N ewborn screening (NBS) for congenital
hypothyroidism (CH) has been ongoing in many developed countries since
the early 1970s [1]. Interestingly, published studies on NBS for CH in
India date to the early-1980s, only a few years after its implementation
in Canada [2]; yet NBS for CH is still not widespread here. Over the
years, a number of successful Indian NBS pilots for CH (and various
other screening conditions) have supported the need for a national NBS
initiative [3]. Researchers have repeatedly demonstrated the presence of
CH in the Indian population along with the availability and value of
early detection and treatment through NBS. Unfortunately, a national NBS
policy aimed at early screening, detection and treatment for CH (or
other screenable conditions) has been slow to evolve. The net result is
thousands of individuals and families who must unnecessarily endure the
adverse consequences of an easily and cheaply treated disease.
Additionally, the resultant intellectual impairment results in a
considerable negative societal impact and health care expense.
In this issue of Indian Pediatrics, the paper
by Verma, et al. [4] adds valuable information to help define the
preferred NBS laboratory process for identifying newborns at increased
risk for CH. It is important that the NBS laboratory protocol minimizes
patient recall for confirmatory testing while not missing true cases, if
possible. This study helps to accomplish that goal by documenting a
model screening laboratory protocol in support of CH screening protocols
and data published recently by the Indian Council of Medical Research
(ICMR) [5,6], and the Indian Society for Pediatric and Adolescent
Endocrinology (ISPAE) [7,8]. It seems that at present there is adequate
published laboratory data, screening and follow-up protocols, and
treatment recommendations, to move forward with a national policy on NBS
for CH (and/or other congenital conditions) and/or a national public
health program for NBS in India.
In NBS, the laboratory screening test(s) performed
must have demonstrated sensitivity and specificity such that as few
individuals as possible are recalled for additional follow-up without
missing true cases of the condition. The specimen matrix must also lend
itself to both an effective and efficient laboratory testing protocol.
In the case of NBS for CH, both thyrotropin (TSH) and thyroxine (T4)
have been, and continue to be, used as productive laboratory screening
tests in screening laboratories around the world. Strategies using
either testing algorithm have long been shown to be effective as
screening methods. As a result of physiologic surges in TSH soon after
birth that might falsely elevate the test result, the use of TSH testing
in newborns who must be screened in the first day of life (for various
reasons, including routine early hospital discharge in some settings) is
sometimes replaced by T4 testing despite its somewhat lower sensitivity
[1,3,7]. Similarly, both liquid cord blood and heel stick specimens
collected on special absorbent paper have been successfully used as the
screening matrix [1,3,7,9]. The preferential use of heel stick blood in
most screening programs results from its ability to provide a
satisfactory specimen for many other metabolic screening tests that are
not possible from cord blood, which can facilitate later program
expansion. These testing and specimen issues and debates are not new in
the NBS world and often the knowledge of the approach of others can
provide a template to move the discussion forward. To this end, it may
be useful to revisit the issues noted by the American Academy of
Pediatrics in the early days of NBS in the US [9].
The apparent incidence of CH, which was thought to be
about 1:3,000 newborns when screening began, now appears to be closer to
1:2,000 newborns, with even higher incidences reported in
iodine-deficient areas, which include parts of India. This means that in
India, over 13,000 babies with CH are either not diagnosed or diagnosed
late each year (assuming 26 million births annually). While the direct
benefit to newborns and their families are obvious, there are also
substantial benefits to society and net cost savings to government
health care costs. While there are many variables to consider in
determining cost benefit, and the value of these variables may differ
markedly from country to country [10,11], I am unaware of a report of
negative cost benefit for CH screening. Indeed, from a purely financial
perspective, cost savings resulting from early diagnosis, treatment and
normal integration into society can have extreme monetary benefit over
time, especially for such a large patient cohort as exists in India. Of
course, the benefits of successful screening extend well beyond
finances.
As the Indian population continues to realize the
benefits resulting from successful public health strategies that have
steadily decreased the infant mortality rate, NBS has become
increasingly important as a preventive public health strategy. The
refinement of screening strategies, such as demonstrated by the study by
Verma, et al. [4], continue to provide the basis for initiation
of a sustainable and productive NBS program. While national
implementation will take time, a national policy supporting initiation
of screening seems attainable, and this will invariably lead to
provincial programs, which can network over time to accomplish a
national screening goal. Building on the recent increased government and
professional interest illustrated here [4] and in other recent reports
[5-8], the time to begin NBS is now. Let’s Just Do It!
Funding: None; Conflict of interest: None
stated.
References
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2. Colaco MP, Desai MP, Ajgaonkar AR, Mahadik CV, Vas
FE, Rege C, et al. Neonatal screening for hypothyroidism. Indian
Pediatr. 1984;21:695-700.
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Newborn screening: need of the hour in India. Indian J Pediatr.
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Jain V, et al. An optimal capillary screen cut-off of thyroid
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9. American Academy of Pediatrics, Committee on
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2013;23:493-500.
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