LAUSR

STUDY QUESTION How well does multi-analyte steroid mass spectrometry (MS) profiling classify women with and without polycystic ovary syndrome (PCOS)? SUMMARY ANSWER Our liquid chromatography MS (LC–MS) steroid profiling only minimally improves discrimination of women with and without PCOS compared with a direct testosterone immunoassay (T_IA) and the free androgen index (FAI). WHAT IS KNOWN ALREADY Blood testosterone measured by direct (non-extraction) immunoassay overlaps between women with and without PCOS. Multi-analyte MS provides greater specificity and accuracy for steroid measurement so might improve the classification. STUDY DESIGN, SIZE, DURATION An observational, cross-sectional study of women with PCOS (n = 152) defined by Rotterdam criteria and matched non-PCOS (n = 45) control women was conducted. PARTICIPANTS/MATERIALS, SETTING, METHODS Serum steroid profiles of testosterone (T), dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), androstenedione (A4), estradiol (E2), estrone (E1), 17 hydroxy progesterone (17OHP4), progesterone (P4) and cortisol were measured by LC–MS; T_IA and sex hormone binding globulin were measured by immunoassay; and FAI, calculated free testosterone (cFT) and total androgen index (TAI) were calculated. Classification was based on logistic regression with corresponding univariate and multivariate C-statistics. MAIN RESULTS AND THE ROLE OF CHANCE Serum testosterone by immunoassay demonstrated levels more than 100% higher than that measured by LC–MS. Compared with the controls, women with PCOS had higher serum T, DHEA, A4, TAI, T_IA, cFT, FAI and E2 but not serum DHT, E1, P4, 17OHP4 or cortisol. Univariate C-statistics were highest for FAI (0.89) and T_IA (0.82) compared with other androgens (T [0.72], DHT [0.40]), pro-androgens (A4 [0.74], DHEA[0.71]) or derivatives (cFT [0.75], TAI [0.60]). For all multivariate models, the overall correct predictions (81–86%) featured high sensitivity (92–96%) but low specificity (28–43%). and substituting LC–MS steroid measurements for T_IA and FAI produced only minimal improvements in classification. LIMITATIONS REASONS FOR CAUTION The study cohort is limited in size and only unconjugated steroids were measured. WIDER IMPLICATIONS OF THE FINDINGS Multi-analyte steroid profiling of unconjugated circulating steroids provides only limited improvement on direct T_IA in classifying women with and without PCOS. STUDY FUNDING/COMPETING INTEREST(S) None. TRIAL REGISTRATION NUMBER N/A.