LC-MS/MS improves screening towards 21-hydroxylase deficiency.

Basal serum 17OHP measurement remains the first screening step for nonclassic congenital adrenal hyperplasia (NCCAH) and the accuracy of the test is of high value. The aim of this study was to compare the accuracy of immunoassays to LC-MS/MS in the assessment of serum 17OHP and androgens concentration in women with hyperandrogenism and controls. 17OHP, total testosterone, androstendione and DHEA-S were measured in 39 women with clinically and/or biochemically evident hyperandrogenism and in 29 age-matched controls without clinical hyperandrogenism. 17OHP and androgens were measured by immunoassays and by LC-MS/MS. In patients group median 17OHP level measured by immunoassays was significantly higher compared to LC-MS/MS (5.49 nmol/l-ELISA NovaTec® and 3.57 nmol/l-ELISA DRG® versus 1.56 nmol/l-LC-MS/MS p < 0.0001) as well as in the control group (2.58 nmol/l-ELISA DRG® versus 1.14 nmol/l-LC-MS/MS p < 0.0001). Additional, unnecessary diagnostic procedures explaining elevated 17OHP level were undertaken in 85% of patients when NovaTec® test was used, in 50% when ELISA DRG® and in none when LC-MS/MS method was applied. Total testosterone, androstendione and DHEA-S concentrations in the patients and the controls assessed by the immunoassays were also significantly higher compared to LC-MS/MS. LC-MS/MS is more reliable diagnostic tool in the measurement of serum 17OHP and androgens concentrations compared to immunoassays in women with hyperandrogenism.