In a recent article, Gupta, et al. [1] reported an important aspect of thyroid metabolism which has great impact on neonatal screening strategy for congenital hypothy-roidism. Prime consideration for a newborn screening program is the cost effectiveness of the exercise; the main determinants of which are the incidence of the disorder, cost of the test as well as the false positive rate.

Authors quote that incidence of congenital hypothyroidism in India detected by neonatal screening is 1:2500 to 1:2800 [2]. However, it is much more common according to recent reports. Authors have not quoted a more recent study [3] which has reported the incidence of congenital hypothyroidism as 1:1700. The ICMR multricentric study [4] covering about 100,000 neonates found the disorder to be occurring with even greater frequency of 1:900 in Tamilnadu and 1:1131 overall. Other published reports (quoted in the paper) - as well as the authors, own data also shows the incidence to be nearer to 1:1000 than 1:2500 [1,5] .

Authors rightly say that perinatal factors affect the cord blood thyroid stimulating hormone (TSH) level. They feel that corrections should be designed to give due consideration to perinatal factors in order to interpret TSH levels. It will be very difficult to design and validate such corrections. Instead, it is advisable to adopt the time- tested approach of screening by heel prick sampling once the TSH surge is over. Blood sampling on day 3 or later is also performed when multianalyte screening is undertaken.

We opine that congenital hypothyroidism – a preventable cause of mental retardation – occurs with significant frequency in India, and a neonatal screening program at national level is the need of the hour. Dry blood sample collected by heel prick after day 3 or day 4 of life is better strategy for neonatal screening as it may avoid false positives because of perinatal factors. This may reduce unnecessary parental anxiety and costs.

1. Gupta A, Srivastava S, Bhatnagar A. Cord blood thyroid stimulating hormone level – interpretation in light of perinatal factors. Indian Pediatr. 2014;51:32-7.

2. Desai MP, Colaco MP, Ajgaonkar AR, Mahadik CV, Vas FE, Rege VV, et al. Neonatal screening for congenital hypothyroidism in a developing country: problems and strategies. Indian J Pediatr. 1987;54:571-81.

3. Devi ARR, Naushad SM. Newborn Screening in India. Indian J Pediatr. 2004;71:157-60.

4. ICMR releases results of study on Congenital Hypothyroidism. March 15, 2013. Chennaionline News. Mht. Available from: http://news.chennaionline.com/chennai/ICMR-releasesresults-of-study-on-Congenital-Hypothyroidism /58cca920 -765d-492b - 8fd3 - 9b34a8ac 2351.col. Accessed February 16, 2014.