Neonatal thyroid screening: Relationship between cord blood thyroid stimulating hormone levels and thyroid stimulating hormone in heel prick sample on 4(th) to 7(th) day-of-life.

Sir,

As no statistically significant difference was observed in the mean serum thyroid stimulating hormone (TSH) values obtained from cord blood (CB) and heel prick (HP), the observation addressed by Seth et al.[1] that the same cut-off value for recall can be used for screening of congenital hypothyroidism (CH) is really interesting. Accordingly, their option to choose TSH-CB rather than TSH-HP in CH screening program seems justifiable. Seth et al.[1] have reported that using TSH-CB in CH screening program offers the advantages of availability in abundance, ethical appropriateness, and ensures compliance since it can be collected in all new-borns before the discharge in hospital. I presume that there are two additional advantages of that option apart from those addressed by Seth et al.[1] These include the following: (1) The TSH-CB screening program has been found to be not affected by non-thyroidal mothers’ diseases, notably toxemia of pregnancy, diabetes mellitus, and positive HIV status.[2] (2) The TSH-CB screening program can be also used as a monitoring tool for the evaluation and control of iodine deficiency disorders in a given population.[234]