[Congenital hypothyroidism missed on newborn screening: report of two cases].

Two male term babies were born at Mackay Memorial Hospital; both were born without incident. Newborn screenings (including phenylketonuria, homocystinuria, galactosemia, congenital hypothyroidism and G-6-PD deficiency) were performed at the age of three days and judged to be normal. In the later neonatal period, case 1 gradually developed prolonged jaundice, poor feeding and poor weight gain. The rechecked thyroid stimulating hormone (TSH) level was 276.3 mU/l. Case 2 was admitted with seizures; the TSH level, rechecked by chance, showing 11.6 mU/l. Under the suspicion of congenital hypothyroidism, serum confirmation tests were performed and showed TSH 393.6 mU/l, 37.09 mU/l and T4 2.87 micrograms/dl, 4.59 micrograms/dl, respectively. The diagnosis was, thus, congenital hypothyroidism with delayed rise in TSH level. The conclusion is that, regardless of the result of newborn screening, a serum confirmation test (T4 & TSH level) should be done in any infant who is suspected to have congenital hypothyroidism.