Finding the right tests…
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Finding the right tests…
Hormonal
This test measures testosterone, the hormone mainly responsible for male sexual development, in your blood. In men, your doctor orders it to investigate low sex drive, erectile dysfunction, infertility, or unexplained muscle and bone loss. In women, the same test is used the other way around — to find out why testosterone might be too high, which can show up as unwanted facial or body hair, acne, or irregular periods. Because testosterone peaks in the morning, the sample is usually drawn between 7 and 10 a.m. for an accurate reading. A single result can't diagnose a condition on its own — your doctor combines it with your symptoms and sometimes a second sample before deciding on next steps.
This test reports testosterone in your blood, either as total testosterone (bound plus free) or, less often, just the free fraction, in nanograms per decilitre. Because testosterone peaks in the morning and drifts lower through the day, the sample is usually drawn between 7 and 10 a.m., and a low or borderline result is often confirmed with a second morning sample before your doctor acts on it. Reference ranges differ sharply by sex and shift with age, so a level normal for a 60-year-old man can look low for a 25-year-old. A single blood draw is all that's needed.
Testosterone drives male sexual development and, in much smaller amounts, contributes to bone density, muscle mass, and mood in women too. In men, it's made mainly by the testicles under signals from the pituitary gland; in women, the ovaries and adrenal glands make smaller amounts.
Doctors order this test in men to investigate reduced sex drive, erectile dysfunction, unexplained fatigue, loss of muscle or bone mass, or infertility. A low result is usually followed by checking LH and FSH too, since those hormones show whether the problem lies in the testicles themselves or in the pituitary signal that drives them.
In women, the same test is used mainly the other way — to investigate signs of testosterone being too high, such as unwanted facial or body hair, acne, irregular periods, or a deepening voice. Polycystic ovary syndrome is the most common cause, though adrenal and, rarely, ovarian tumours can also raise testosterone in women.
Because a single number can't diagnose a condition on its own, your doctor combines your result with your symptoms, examination, and sometimes further hormone tests before deciding what it means.
MedlinePlus reports a typical range of about 249 to 836 ng/dL for men aged 17 to 50, dropping to roughly 193 to 740 ng/dL after age 50. Ranges vary by lab, so check the figures on your own report.
MedlinePlus reports a typical range of about 8.4 to 48.1 ng/dL for women aged 17 to 50, and 2.9 to 40.1 ng/dL after age 50 — much lower than the male range, since testosterone plays a smaller role in women.
Testosterone peaks in the morning and declines through the day, so testing between 7 and 10 a.m. gives the most reliable and comparable reading. A sample drawn in the afternoon can look lower even in someone with normal testosterone.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
Not necessarily. Because levels vary day to day and testosterone can dip temporarily with illness, poor sleep, or stress, doctors usually confirm a low or borderline result with a second morning sample before making a diagnosis.
In men with a low result, doctors often also check LH and FSH, since these show whether the problem lies in the testicles or in the pituitary gland that signals them. In women, tests for PCOS or adrenal function may be added.
No special preparation, including fasting, is generally needed, though your doctor may combine it with other tests that do require fasting.