Hormonal diagnosis of 21-hydroxylase deficiency in plasma and urine of neonates using benchtop gas chromatography-mass spectrometry

We aimed at measuring the first plasma concentrations of 17-hydroxyprogeste rone (17OH-P) determined by benchtop isotope dilution/gas chromatography-ma ss spectrometry (ID/GC-MS) in term neonates with or without 21-hydroxylase deficiency. Plasma samples from normal cord blood specimens (n = 30), unaff ected neonates (n = 38) and neonatal patients with classical 21-hydroxylase deficiency (eight salt-wasters, three simple virilizers) were analyzed. St eroid profiling of random urinary specimens by CC-MS sen ed as a confirmato ry test for 21-hydroxylase deficiency. 17OH-P (nmol/l) in cord blood plasma lay between 11.66 and 75.92 (median 24.74). It declined shortly after birt h. In the first 8 days of life, the time that screening for 21-hydroxylase deficiency is performed, 17OH-P ranged between undetected levels and an upp er limit of 22.87 (median 4.11). Thereafter (days 9-28) its concentrations lay between 2.18 and 20.30 (median 6.22). Except one simple virilizer, all other patients with 21-hydroxylase deficiency had clearly elevated plasma 1 7OH-P at the time that screening for 21-hydroxylase deficiency would be per formed. We suggest ID/GC-MS, which provides the highest specificity in ster oid analysis, for checking suspicious concentrations of 17OH-P in neonates and underscore the potential of urinary steroid profiling by GC-MS as a rap id, noninvasive and non-selective confirmatory test for congenital adrenal hyperplasia.