False negative 17-hydroxyprogesterone screening in children with classical congenital adrenal hyperplasia.

We report 5 out of 214 children with classical congenital adrenal hyperplasia (CAH) that was not detected by neonatal 17-Hydroxyprogesterone screening. Therefore, diagnosis was only based on a suspect clinical picture and subsequent re-evaluation. In addition to 3 patients suffering from the simple virilizing form of CAH and not reported so far, the remaining 2 children whose CAH was missed by the screening suffered from the severe salt-wasting form. This report underlines the importance of a careful clinical investigation of newborns to detect signs of genital virilization. The differential diagnosis of classical CAH should be kept in mind even if neonatal screening is reported to be normal.