Diagnostic value of total testosterone and free androgen index measured by LC–MS/MS for PCOS and insulin resistance

BACKGROUND: The objective of the study was to explore the clinical significance of steroid hormones in the diagnosis of PCOS and PCOS‐related insulin resistance through liquid chromatography–mass spectrometry/mass spectrometry (LC–MS/MS) and chemiluminescent immunoassay (CLIA). METHODS: The study included 114 patients with PCOS and 100 controls. Steroid hormone levels in serum were measured using LC–MS/MS and CLIA. The Bland–Altman method was used to check the consistency between the two methods. The diagnostic value of the LC–MS/MS method for female hyperandrogenemia and PCOS was evaluated. RESULTS: Women with PCOS were younger than controls on average (p < 0.001). PCOS patients had higher luteal hormone (LH, p < 0.001), insulin (p = 0.002), estradiol (E2, p < 0.001), total testosterone (TT, p < 0.001), free androgen index (FAI, p = 0.021), dehydroepiandrosterone sulfate (DHEA, p = 0.021), insulin resistance index (HOMA‐IR) (p = 0.034), and fasting glucose (p = 0.017) levels than controls as measured by CLIA. The diagnostic value of TT was the best, and the area under the AUC curve was 0.766. Women with PCOS had higher androstenedione (A2, p < 0.001), FAI (p < 0.001), TT (p < 0.001), and 17‐hydroxyprogesterone (17‐OHP, p < 0.001) levels than controls as measured by LC–MS/MS. The ROC curve showed that the diagnostic efficacy of A2, TT, and 17‐OHP was 0.830, 0.851, and 0.714, respectively. The consistency of TT detected by LC–MS/MS and CLIA was poor according to the Bland–Altman method. Detected TT by LC–MS/MS had the highest diagnostic efficiency for PCOS. The diagnostic power of the LC–MS/MS results for PCOS‐related insulin resistance was analyzed. The results showed that the FAI had the highest diagnostic power, with an ROC curve of 0.798. CONCLUSION: LC–MS/MS is more sensitive and accurate than CLIA in the determination of serum TT and FAI. TT is more effective for the diagnosis of PCOS, whereas FAI is more valuable in the diagnosis of insulin resistance.