Total Testosterone
Testosterone is the primary male sex hormone, produced mainly by the testes in men and in smaller amounts by the ovaries and adrenal glands in women. Total testosterone measures all circulating testosterone — about 98% bound to SHBG or albumin, and 2% free. Sample should be collected in the morning (peak levels) and fasting is preferred. In men, it is the first test for hypogonadism; in women, it is measured when hirsutism, acne, or virilization suggests excess.
Reference Ranges
Male
300 – 1000
ng/dL
Female
15 – 70
ng/dL
Child
Consult pediatrician
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
In men, total testosterone below 300 ng/dL suggests hypogonadism. Confirmed low testosterone (on two morning samples) with symptoms — low libido, erectile dysfunction, fatigue, muscle loss, mood change — warrants evaluation for cause (pituitary, testicular, medication-related, obesity, sleep apnea) and consideration of testosterone replacement. In women, very low testosterone may contribute to reduced libido but is rarely the sole cause.
What High Levels Mean
In men, high testosterone (often from exogenous anabolic steroids) causes suppression of the pituitary-testicular axis, infertility, testicular atrophy, erythrocytosis, acne, and cardiovascular risk. In women, high testosterone with hirsutism, acne, or oligomenorrhea suggests PCOS (the most common cause), adrenal hyperplasia, ovarian or adrenal tumor (if very high), or exogenous androgen use.
Frequently Asked Questions
Do I need to fast before a testosterone test?
Yes. Testosterone follows a diurnal rhythm — highest in the early morning, lowest in the late evening. Testing should be done before 10 AM, and ideally fasting since food can transiently lower testosterone. Two separate confirmatory samples are needed before diagnosing low testosterone and starting replacement.
What does total testosterone miss?
In older men, obese men, men on oral estrogens, and in liver disease, SHBG is often abnormal. This changes the ratio of bound to free testosterone, so total testosterone may be normal while free testosterone (bioavailable) is low and symptoms persist. In these situations, measuring SHBG and calculating free testosterone is essential.
Should women with PCOS get testosterone tested?
Yes — testosterone along with DHEAS, 17-OHP, SHBG, and free testosterone is part of the hyperandrogenism workup in PCOS. Mild elevation is common. Very high testosterone (>150 ng/dL in women) warrants urgent investigation for adrenal or ovarian tumor, which is rare but dangerous. PCOS is diagnosed using the Rotterdam criteria, which include clinical or biochemical hyperandrogenism.
Related Hormones tests
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Pancreatic hormone that controls blood sugar.
µIU/mLHormonesHOMA-IR (Insulin Resistance Index)
Calculated index that estimates insulin resistance.
indexHormonesBeta-hCG (Human Chorionic Gonadotropin)
Pregnancy hormone — also a tumor marker for certain cancers.
mIU/mLHormonesSex Hormone Binding Globulin (SHBG)
Protein that binds sex hormones in blood, controlling their availability.
nmol/LThis information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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