Distinguishing Obstructive from Non-obstructive Azoospermia and Necessity of Diagnostic Testis Biopsy

Background: Accurate etiology of azoospermia is required for optimal management of patients. This study aimed to determine serum hormonal level and testicular long-axis cut-off points to distinguish obstructive azoospermia (OA) from non-obstructive azoospermia (NOA) in Iranian patients. Moreover, the necessity of diagnostic testis biopsy in azoospermic patients was evaluated. Methods: In this retrospective study, data from 471 azoospermic patients such as history and physical examination, serum hormonal level, semen fluid parameter, and testicular long axis based on ultrasound were evaluated from 2016 to 2020. All patients were examined by a single urologist and underwent a diagnostic testis biopsy for a definite diagnosis. The diagnostic parameters were analyzed using SPSS software version: 26. Statistical tests such as t test and Chi square tests and receiver operating characteristic (ROC) curves were used to distinguish NOA from OA. Results: A total of 127 patients with OA and 284 with NOA were included in the study. The mean serum testosterone level was significantly higher in OA than NOA (4.2 vs. 3.4 ng/mL), whereas the mean serum follicular stimulating hormone (FSH) (5.3 vs. 19.1 mIU/mL) and Luteinizing hormone (LH) (5.3 vs. 11 mIU/mL) were lower in OA group. The ROC curve analysis indicated that FSH and the testicular long axis were the best diagnostic predictors. Using a combination of serum FSH (8.9 mIU/mL) and testicular long axis (39mm), the positive predictive value for NOA and OA was 97.02% and 78.8%, respectively. Conclusion: A combination of serum FSH higher than 8.9 mIU/mL and testicular long axis lower than 39 mm were strong predictors to distinguish NOA from OA in our Iranian patients. In addition, diagnostic testicular biopsy seems to be necessary for patients with OA and NOA characteristics. Keywords * Azoospermia * Follicle stimulating hormone * Luteinizing hormone * Testosterone * Biopsy