Testosterone, Total (Serum or Plasma)

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like low libido, fatigue, or changes in body hair. It could also be part of evaluations for infertility, menstrual irregularities, or conditions affecting hormone production, such as hypogonadism or polycystic ovary syndrome (PCOS). In men, it may be checked during evaluations for low testosterone-related symptoms like reduced muscle mass or mood changes.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the draw if your lab uses a specific method. Avoid alcohol for 24 hours before testing. If you’re taking medications that affect hormone levels, let your provider know.

What the Results Mean

Results are compared to reference ranges based on age, sex, and health status. While ranges vary, lower-than-expected levels may indicate hormone deficiencies, while higher levels could signal conditions like Cushing’s syndrome or tumors. Your provider will interpret results in the context of your overall health and symptoms.

Common Conditions Affecting Testosterone Levels

Conditions like pituitary disorders, kidney or liver disease, obesity, or certain medications can influence testosterone levels. Chronic illnesses, stress, or aging may also play a role. If you have a history of these factors, your provider will consider them when reviewing your results.