Performance of Total Testosterone Measurement to Predict Free Testosterone for the Biochemical Evaluation of Male Hypogonadism

Total testosterone between 280 and 350 ng/dl is not sensitive enough to reliably exclude hypogonadism. Total testosterone must exceed 350 to 400 ng/dl to reliably predict normal free testosterone. Except when levels are less than 150 ng/dl total testosterone measurement has low specificity for the biochemical diagnosis of hypogonadism.