Congenital hypothyroidism is not always permanent: caveats to newborn thyroid screen interpretation.

Congenital hypothyroidism (CH) fulfills all the pre-requisites for being included in a newborn screening (NS) program. It does not present clinical features early and delayed diagnosis has disastrous consequences. Accurate biochemical diagnosis is possible before clinical features set in, and treatment by 2 to 3 weeks of age ensures good outcome. For India, two more important pre-requisites are fulfilled: CH is common (about 1 in 3000 infants) and its treatment is very easily affordable. Thyroid NS can be performed by measurement of TSH (commonly employed world wide) or T4 on cord blood or a neonatal sample at least 48 after birth. Like so many other initiatives in India, pediatricians and obstetricians have begun to recommend thyroid NS from their own health care facility, instead of waiting for the government to set up regional newborn screen programs. This has resulted in large numbers of timely diagnoses. It has also made it necessary for pediatricians to educate themselves on the caveats of thyroid NS.