Transient Neonatal Hypothyroidism Detected by Newborn Screening Program

A screening program for the detection of neonatal hypothyroidism has been in effect in Oregon since May 1975. Blood samples are obtained from all newborn infants to test for phenylketonuria and other metabolic diseases. A second specimen is obtained from more than 90% of these infants who are retested at 4 to 6 weeks of age. These Guthrie filter paper blood samples are analyzed for thyroxine (T4), and all samples with a low T4 value are analyzed for thyroid stimulating hormone (TSH). At the outset of the program, it was speculated that the screening might detect infants who had reduced