Distinguishing non-obstructive azoospermia from obstructive azoospermia in Taiwanese patients by hormone profile and testis size.

BACKGROUND: An accurate diagnosis of the etiology of azoospermia is crucial, as sperm retrieval methods differ between patients with non-obstructive azoospermia (NOA) and obstructive azoospermia (OA). The aim of this study was to determine hormone and testes size cutoff values to identify the cause of azoospermia in Taiwanese patients.

METHODS: The medical records of azoospermic patients were retrospectively collected from April 2008 to July 2016, including hormone profile, physical examination findings, and testes size. Bilateral testes biopsies or microdissection testicular sperm extraction were performed in all patients for a definite diagnosis. The diagnostic parameters used to distinguish NOA from OA were analyzed using the t-test and receiver operating characteristic curves.

RESULTS: A total of 51 patients with OA and 156 with NOA were included. The mean levels of testosterone (4.5 vs. 3.4 ng/ml) and E2 (26.3 vs. 19.2 pg/ml) were significantly higher in the OA group, whereas the levels of follicular stimulating hormone (FSH) (5.6 vs. 25.4 mIU/ml) and Leutinizing hormone (LH) (3.7 vs. 11.6 mIU/ml) were lower. Receiver operating characteristic curve analysis revealed that FSH and right testis size were the best individual diagnostic predictors. Using a combination of FSH >9.2 mIU/ml and right testis size <15 ml, the positive predictive value for NOA was 99.2% and 81.8% for OA.

CONCLUSION: A combination of FSH >9.2 mIU/ml and right testis size <15 ml was a strong predictor of NOA in our Taiwanese patients.