Androgens by immunoassay and mass spectrometry in children with 46,XY disorder of sex development

Abstract

Objective: Steroid measurement is a challenge in pediatric endocrinology. Currently, liquid chromatography with tandem mass spectrometry (LC-MS/MS) is considered a gold standard for this purpose. The aim of this study was to co mpare both LC-MS/MS and immunoassay (IA) for androgens before and after human recom binant chorionic gonadotropin (rhCG) stimulus in children with 46,XY disorders o f sex development (DSD). Methods: Nineteen patients with 46,XY DSD were evaluated; all of them w ere prepubertal and non-gonadectomized. Testosterone, dihydrotestosterone (DHT), DHEA and androstenedione were measured by IA and LC-MS/MS before and 7 d ays after rhCG injection. The correlation between IA and LC-MS/MS was analyzed by the intraclass correlation coefficient (ICC) and Spearman’s rank correlation coe fficient (SCC). For concordance analysis the Passing and Bablok (PB) regression and the Bland and Altman (BA) method were used. Results: Testosterone showed excellent correlation (ICC = 0.960 and SCC = 0.964); DHT showed insignificant and moderate correlations as indicated by I CC (0.222) and SCC (0.631), respectively; DHEA showed moderate correlation (ICC = 0.585 and SCC = 0.716); and androstenedione had poor and moderate correlations in ICC ( 0.363) and SCC (0.735), respectively. Using the PB method, all hormones showed a linear correlation, but proportional and systematic concordance errors were detected fo r androstenedione, systematic errors for testosterone and no errors for DHEA and D HT. By the BA method, there was a trend of IA to overestimate testosterone and andros tenedione and underestimate DHEA and DHT when compared to LC-MS/MS. Conclusion: Traditional IA should be replaced by LC-MS/MS for the androgen s measurement in prepubertal children whenever is possible.

Keywords

• testosterone
• testicles
• androstenedione
• androgen insensitivity syndrome
• 5α-reductase