The determination of total testosterone and free testosterone (RIA) are not applicable to the evaluation of gonadal function in HIV-infected males.

Introduction: Hypogonadism is common in human immunodeficiency virus (HIV)-infected men; the high concentration of sex hormone binding globulin (SHBG) in this population, induces a "false increase" in total testosterone (TT) values.

Aims: To validate the determination of TT and measured free testosterone (FT [radioimmunoassay {RIA}]) for hypogonadism diagnosis in an HIV-infected population using calculated free testosterone (CFT) as reference method; and also to determine the prevalence and identify the risks factors of hypogonadism.

Methods: Cross-sectional, observational study. Ninety HIV-infected males (42 ± 8.2 years), not HCV coinfected, antiretroviral therapy (ART)-naive (14 patients), on current ART with enhanced protease inhibitor (PI) (39 patients), or patients on PI-naive ART (NN) (37 patients).

Main Outcome Measures: CFT was calculated by determining TT, SHBG, and albumin (Vermeulen's formula); hypogonadism was defined as CFT <0.22 nmol/L (reference range for young healthy males in our laboratory); sensitivity of TT and FT (RIA) for hypogonadism diagnosis was calculated.

Results: Twelve patients (13.3%, 95% confidence interval [CI] 7.8-21.9) by CFT presented hypogonadism. TT and FT (RIA) presented a sensitivity of less than 30% in the diagnosis of hypogonadism. Logistic regression multivariate analysis confirmed an independent association between hypogonadism, the patient's age per decade, odds ratio (OR) 6.9 (CI 1.9-24.8; P = 0.003), and longer duration of HIV infection per decade, OR 13.1 (CI 1.3-130.6; P = 0.02). Hypogonadism was associated with erectile dysfunction.

Conclusions: TT and FT (RIA) are not useful in the differential diagnosis of hypogonadism in HIV-infected males. There is a significant prevalence of hypogonadism in HIV-infected males, with the patient's age and duration of the disease being the only identifiable risk factors.