Total Testosterone

Testosterone (total), serum testosterone, free testosterone

This test measures the level of the hormone testosterone in your blood. Testosterone is a male sex hormone (androgen) that helps male features develop. Testosterone is made in the testes, the ovaries, and the adrenal glands.

Testosterone causes the changes that occur during male puberty. It helps hair, muscles, the penis, and the testes to grow. Testosterone also causes the voice to deepen. In adults, testosterone boosts sex drive and helps the sperm mature.

The ovaries make small amounts of testosterone. It helps many organs and body processes in those who are biologically female.

The pituitary gland in your brain controls the amount of testosterone your body makes. It does this by using other signaling hormones, such as luteinizing hormone.

Most of the testosterone in the blood attaches to two proteins. These proteins are albumin and sex hormone binding globulin. Some testosterone is not attached to proteins. This testosterone is called free testosterone. Free testosterone and albumin-bound testosterone are also referred to as bioavailable testosterone. This is the testosterone that is easily used by your body.

If your doctor thinks that you have low or high testosterone, they will first test total testosterone levels. This looks at all 3 types of testosterone. The free testosterone can help give more information when total testosterone is low.

Anyone can have health problems because of low or high levels of testosterone. Those who are biologically female and who have high levels of testosterone may have polyendocrine metabolic ovarian syndrome (PMOS). This condition can cause:

• Infertility.
• Lack of menstruation.
• Acne.
• Obesity.
• Blood sugar problems that can lead to type 2 diabetes.
• Extra hair growth, especially on the face.

Testosterone levels in those who are biologically male drop as they age. This is not considered to be hypogonadism. The U.S. Food and Drug Administration (FDA) currently advises against treating low testosterone caused only by aging.

You may need this test if you have symptoms of low testosterone.

• Male symptoms:
  • Large breasts.
  • Low sex drive or lack of interest in sex.
  • Trouble getting an erection.
  • Low sperm count and other fertility problems.
  • Changes in the testicles.
  • Weak bones.
  • Irritability.
  • Trouble concentrating.
  • Loss of muscle mass.
  • Hair loss.
  • Depression.
  • Fatigue.
  • Anemia.
• Female symptoms:
  • Fertility problems.
  • Missed or irregular menstrual periods.
  • Osteoporosis.
  • Low sex drive.
  • Changes in breast tissue.
  • Vaginal dryness.

You may also have other blood tests to check hormone levels. These include:

• Follicle-stimulating hormone test.
• Luteinizing hormone test.
• Thyroid stimulating hormone test.
• Prolactin test.

You may also need to have:

• Biopsy of the testicles.
• Imaging test, such as an MRI scan of the pituitary.
• Semen analysis.
• Central hormones (tests of the pituitary gland).

Test results may vary depending on your age, sex, health history, and other things. Your test results may be different depending on the lab used. Ask your doctor what your test results mean for you.

The results of this test are given in nanograms per deciliter (ng/dL). Normal test results show total testosterone levels of:

• 270 to 1,070 ng/dL (male, depending on age).
• 15 to 70 ng/dL (female).

If your testosterone levels are higher or lower than normal, you may have a condition that affects your testosterone production. If your levels are higher than normal, you may have a tumor on the testes or ovaries.

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. This test is usually done in the morning. This is because testosterone levels tend to be highest at that time. But you may need to have this test more than once, and at different times of the day, to confirm low testosterone levels. This is because your testosterone level can change from morning to evening and from day to day.

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

Some medicines may affect your test results. These include hormone medicines and antifungal medicines, such as ketoconazole. Some foods that have phytoestrogen can also affect testosterone levels. These include some fruits and vegetables, wine, and tea. Having the test done late in the day may show that your testosterone level is lower than it really is.

You don't need to prepare for this test. But be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any drugs you may use.