Comparing calculated free testosterone with total testosterone for screening and diagnosing late-onset hypogonadism in aged males: A cross-sectional study.

OBJECTIVE: The aim of this study is to compare calculated free testosterone (cFT) and total testosterone (T) in predicting late-onset hypogonadism (LOH) in middle-aged and elderly males.

METHODS: We surveyed a random sample of 608 males between the ages of 45 and 87 years from Shanghai, China. The Aging Male Symptoms (AMS) questionnaire and the Androgen Deficiency in Aging Male (ADAM) questionnaire were completed by the subjects. Testosterone (T), sex hormone-binding globulin (SHBG), albumin, and other blood biochemical indexes were measured in 332 males. The corresponding cFT was obtained using the Vermeulen formula and the correlations between T and cFT were analyzed by SPSS statistical software.

RESULTS: Among the 332 males who underwent biochemical evaluation, 289 males (87.0%) was positively screened by the ADAM questionnaire and 232 males (69.9%) by the AMS questionnaire. As suggested by linear regression, cFT exhibited a negative correlation with age in both ADAM+ and AMS+ group, whereas T did not appear to have significant correlation with age. Besides, there were statistically significant differences in cFT (P<.001) in the AMS questionnaire.

CONCLUSIONS: Calculated free testosterone levels are more reliable than T levels for diagnosing LOH in middle-aged and elderly males.