Abstract
Misdiagnosed cases of congenital-hypothyroidism (CH) during the first 9 years of the French screening program were analysed. A total of 50 cases were missed (3% of total diagnosed) which represents a severe failure of the system. Failures were caused by technical errors of sample collection or TSH assay (n=27) or due to normal TSH (n=22) or T4 (n=1) concentrations in the newborn blood specimens. We conclude that screening methods should be improved and that physicians should remain alert to clinical signs of hypothyroidism.