Testosterone measurements in early infancy

Circulating testosterone concentrations in infants measured by a direct chemiluminescent immunoassay ( Bayer ADVIA Centaur) were compared with those measured by a traditional radioimmunoassay using solvent extraction. The results confirm that neonatal circulating testosterone concentrations are method dependent, and each laboratory should establish method related reference ranges especially if using a direct commercial immunoassay. The results indicate that the Bayer ADVIA Centaur procedure can be used reliably in neonates. Expected values for male and female infants, 10 days old were 2.5 - 11.1 ( n = 36) and 1.7 - 5.6 ( n = 36) nmol/l respectively. For older neonates ( 10 50 days) the ranges were 0.2 - 17.2 ( n = 42) and 0.1 - 1.5 ( n = 7) nmol/l respectively.