C11-oxy C 19 and C11-oxy C 21 steroids in neonates: UPC 2 -MS/MS quantification of plasma 11β-hydroxyandrostenedione, 11-ketotestosterone and 11-ketoprogesterone.

The purpose of this study was to identify the C11-oxy C19 and C11-oxy C21 steroids in male and female neonate plasma. At birth, the most abundant C11-oxy steroids detected in neonatal plasma were 11β-hydroxyandrostenedione, ∼13 nM, and 11-ketoprogesterone, ∼23 nM. C11-oxy C19 steroids were higher than C19 steroids in neonatal plasma, 22.2 nM vs 5.4 nM. The inclusion of C11-oxy C19 and C21 steroid reference ranges in routine steroid analyses will assist the characterization of disorders associated with impaired steroidogenic enzyme expression and the identification of potential biomarkers.