Performance of mass spectrometry steroid profiling for diagnosis of polycystic ovary syndrome

Abstract

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.