Accurate diagnosis of testosterone deficiency requires confirming low circulating levels alongside clinical symptoms. Practice guidelines mandate obtaining at least two separate morning fasting total testosterone levels.
Free or bioavailable testosterone is measured to evaluate biologically active hormone, especially in men with altered sex hormone-binding globulin (SHBG) due to age, obesity, or metabolic conditions.
Safety baseline testing includes a complete blood count (CBC) to check baseline hematocrit, prostate-specific antigen (PSA) to screen for prostate abnormalities, liver and kidney function via a metabolic panel, a lipid panel, and gonadotropins (LH and FSH) to differentiate primary from secondary hypogonadism.
Risks and limitations
- A single borderline lab result is insufficient to confirm a diagnosis; testing must be repeated in the morning while fasting.
- Abnormal baseline findings in hematocrit, PSA, or liver enzymes must be clinically evaluated prior to considering therapy initiation.