Alphafetoprotein in screening for congenital hypothyroidism.

This study was conducted on 500 full-term neonates and 25 older patients with congenital hypothyroidism (CH), newly or previously diagnosed. Alphafetoprotein (AFP) was elevated in two neonates. In one, persistent elevation of AFP and thyroid stimulating hormone (TSH) with low thyroxine (T4) were found (congenital hypothyroidism). In the other, AFP, TSH and T4 levels normalized (transient hypothyroidism). The mean AFP level in new CH patients was significantly higher than in previously diagnosed patients, and was higher in CH patients than in controls. Significant relationships were found between AFP and T4, AFP and TSH, and AFP and age. AFP is a sensitive indicator of thyroid status and can be used as a screening test for hypothyroidism from the first day of life and in follow-up of CH patients.