OBJECTIVETo detect the levels of seminal plasma leptin (SPL) and serum leptin (SL) in patients with azoospermia, and to explore the methods of using SPL and SL alone or the combination of SPL, SL and follicle stimulating hormone (FSH) for the differential diagnosis of obstructive azoospermia (OA) and non-obstructive azoospermia (NOA).

METHODSWe enrolled in this study 45 patients with diagnosed OA, 41 with unexplained NOA and 30 men with normal semen parameters as controls. The azoospermia patients underwent percutaneous aspiration from the epididymis (PESA) or aspiration/extraction from the testis (TESA/TESE), and all the subjects were detected for the levels of serum FSH, SPL and SL. Individual and multiple indexes were evaluated by Fisher's discriminant analysis combined with ROC curve analysis.

RESULTSThere were no significant differences in the body mass index (BMI) among the three groups. Compared with the normal control, the OA patients showed an obviously elevated level of SPL (P = 0.048), and the NOA patients remarkably increased levels of FSH (P = 0.000), SL (P = 0.000) and SPL (P = 0.000). In comparison with the OA group, the levels of FSH (P = 0.000), SL (P = 0.006) and SPL (P = 0.033) were significantly increased in the NOA group. For the differential diagnosis of OA and NOA, the areas under the ROC curve of SPL and SL were 0.658 (P = 0.014) and 0.702 (P = 0.002) , respectively, both significantly greater than 0.5, while that of the combination of SPL, SL and FSH was the greatest (0.953). In addition, with 0.026 x SPL +0.05 x SL +0.106 x FSH -2.197 as the combined indicator value and -0.289 as the cut-off value (> or = cut-off value for NOA), the sensitivity and specificity of the combination were 0.878 and 0.902, respectively, both reached the maximum.

CONCLUSIONBoth the levels of SPL and SL are valuable for the differential diagnosis of OA and NOA, but the joint consideration of SPL, SL and FSH may provide better indicators.