Diagnosis and Evaluation of Hypogonadism.

A systematic approach to diagnose hypogonadism initially establishes the presence of symptoms/signs of testosterone deficiency, considers other potential causes of manifestations, and excludes conditions that transiently suppress testosterone. Hypogonadism is confirmed by measuring fasting serum total testosterone in the morning on at least 2 separate days, or free testosterone by equilibrium dialysis or calculated free testosterone in men with conditions that alter sex hormone-binding globulin or serum total testosterone near lower limit of normal. To guide management, further evaluation is performed to identify the specific cause of hypogonadism and whether it is potentially reversible or an irreversible pathologic disorder.