1 Division of Endocrinology, Children's Memorial Hospital, Chicago, IL 60614
Two recent publications by authoritative groups1.2 have pointed out the value of thyroxine screening of all newborn infants in an effort to diagnose hypothyroidism early. Both statements advised caution in undertaking mass screening programs without an advisory committee and supporting services; in spite of these cautions, many hospitals with delivery services have now begun screening programs without such ancillary services. As a result, the aim of utilizing screening for the detection of hypothyroidism has been obscured because physicians and laboratories performing these assays have never established an upper limit of normal for thyroxine assays in neonates by the various methodologies in use.