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Overview

What Is a Testosterone Blood Test?

A testosterone blood test measures the amount of testosterone in a sample of blood. It may measure total testosterone, which includes testosterone attached to proteins and testosterone circulating freely, or free testosterone, the unbound portion. Results are interpreted with symptoms, age, sex, the time of collection, and the laboratory’s reference range.

What does testosterone do?

Testosterone is a hormone involved in sexual development, sex drive, sperm production, muscle and bone maintenance, and the development of body hair and other physical traits. It is produced mainly by the testes, with smaller amounts made by the adrenal glands; people of all sexes have testosterone. A clinician may order total testosterone, free testosterone, or related hormone tests because one result may not fully explain symptoms or hormone activity. Testosterone testing can help investigate concerns involving sexual health, fertility, puberty, menstrual changes, or other endocrine conditions.

When It Is Needed

When Is Testosterone Testing Needed?

Testing is usually ordered when symptoms, a medical condition, or a treatment decision raises a question about testosterone levels. A clinician may also use it to evaluate hormone-related treatment or monitor a known condition. Symptoms alone do not prove that testosterone is abnormal, and routine testing is not appropriate for everyone.

  • Possible symptoms of low testosterone or another hormone problem, such as reduced sex drive, erectile difficulties, fatigue, or loss of muscle or body hair
  • Possible signs of unusually high testosterone or excess androgen activity
  • Evaluation of infertility, delayed or early puberty, or changes in menstrual periods
  • Monitoring of known hormone conditions or testosterone treatment

Preparation

How to Prepare for a Testosterone Blood Test

Ask the ordering clinician or laboratory for exact instructions before your testosterone level test. Preparation can vary depending on whether other tests are included in the panel and why the test was ordered.

  • Ask whether the sample should be collected in the morning.
  • Confirm whether fasting is required for the ordered test or test panel.
  • Tell the clinician about medicines, supplements, and testosterone or steroid products.
  • Follow instructions about exercise, illness, and repeat testing if provided.
  • Drink water as instructed, unless you have been given different fluid restrictions.

During the Test

What Happens During the Testosterone Blood Test?

A testosterone blood test is usually a single-session venous blood draw. A healthcare professional cleans the skin, inserts a small needle into a vein, collects blood into one or more tubes, removes the needle, and applies pressure and a bandage.

What does the blood draw feel like?

The draw usually takes only a short time. You may feel a brief sting when the needle enters, followed by pressure, and you may have minor soreness or bruising afterward. If you tend to feel light-headed during blood draws, tell the staff and ask to sit or lie down. An at-home testosterone test kit may use a different collection method, so follow its instructions exactly and check whether the sample is processed by an accredited laboratory.

Risks

Risks of a Testosterone Blood Test

  • Brief pain or stinging when the needle is inserted.
  • Minor bruising, soreness, or bleeding at the puncture site.
  • Light-headedness or fainting during or shortly after the blood draw.
  • Rare infection, significant swelling, or ongoing bleeding.

After the blood draw

When to seek help

Contact a healthcare professional if the puncture site develops increasing redness, warmth, swelling, severe pain, pus, or bleeding that does not stop with firm pressure.

Results

Understanding Testosterone Blood Test Results

Reports commonly show a numeric total testosterone result, its units, and a laboratory-specific reference range. Some panels also report free testosterone and related markers, such as proteins or other hormones that help with interpretation.

Total testosterone and free testosterone

Total testosterone includes both protein-bound testosterone and the unbound hormone circulating in the blood. Free testosterone is the unbound portion that is available to tissues. Results can vary with the time of day, age, sex, puberty or menopause status, illness, medicines, laboratory method, and whether the sample was collected as instructed. For that reason, testosterone levels should be interpreted in context rather than compared with a generic number found online.