Exploratory Evaluation of Combined Hormonal Indices in Non-Obstructive Azoospermia: Diagnostic Performance and Prediction of TESE Success

Background: The aim of this study was to evaluate the diagnostic performance of combined testicular function indices in patients with non-obstructive azoospermia and to investigate the clinical value of these indices in predicting the diagnosis of non-obstructive azoospermia and the success of testicular sperm extraction. Methods: This retrospective observational study included 224 male patients who underwent infertility assessment. The patients were classified into a normospermic group (n = 165) and a non-obstructive azoospermia group (n = 59). Serum anti-Müllerian hormone, follicle-stimulating hormone, luteinising hormone and total testosterone levels were assessed. The Testicular Function Index, the modified Testicular Function Index and the logarithmically transformed index were calculated. Patients in the non-obstructive azoospermia group underwent micro-TESE and were classified according to sperm retrieval status. Diagnostic performance was assessed using ROC analysis. Results: Among the 59 patients with non-obstructive azoospermia who underwent micro-TESE, sperm retrieval was successful in 26 patients and unsuccessful in 33 patients. In the non-obstructive azoospermia group, anti-Müllerian hormone and testosterone levels were lower, whilst follicle-stimulating hormone and luteinising hormone levels were higher (all p < 0.001). All combined indices were found to be significantly lower in the non-obstructive azoospermia group (all p < 0.001). In the ROC analysis, follicle-stimulating hormone demonstrated the highest discriminatory performance (AUC = 0.978). In the testicular sperm extraction analysis, anti-Müllerian hormone was found to be the marker with the highest performance (AUC = 0.930). Conclusions: (Follicle-stimulating hormone demonstrated the highest diagnostic performance for distinguishing non-obstructive azoospermia, whereas anti-Müllerian hormone was the strongest predictor of TESE success. Although the combined testicular function indices showed good diagnostic performance, they did not outperform these established hormonal markers and should therefore be regarded as complementary tools for the integrated assessment of testicular function. These findings should be considered exploratory and require further validation.