What Is Testosterone?

Testosterone is the main sex hormone in males. It is made in the testicles and adrenal glands. It spurs the development of typical male features such as body hair and a deep voice. It is important for fertility, sex drive, and muscle and bone mass.

Testosterone is present in females but in lesser amounts.

Reason for the Test

The test is called total testosterone. It measures the amount in the blood and what is bound to a certain protein. It is used to find the cause of symptoms that points to a problem with testosterone levels. For males, these include:

• Erectile dysfunction
• Low sex drive
• Bone loss or anemia
• Fertility problems
• Hormone problems at any age

Females can be checked for problems with having masculine features or fertility.

Another test is called free testosterone. This is not reliable on its own. But it can be measured with total testosterone in some cases.

Type of Sample Taken

A blood sample will be taken from a vein in the arm.

Prior to Collecting the Sample

Tell your doctor about any medicines or supplements you are taking. They may affect the test results.

During the Sample Collection

You will be asked to sit. An area inside your elbow will be cleaned. A large band will be tied around your arm. The needle will then be inserted into a vein. A tube will collect the blood from the needle. The band on your arm will be removed. Once all the blood is collected, the needle will be removed. Some gauze will be placed over the site to help stop bleeding. You may also be given a bandage to place over the site. The process takes about 5 to 10 minutes.

After Collecting the Sample

After the blood sample is taken, you may need to stay seated for 10 to 15 minutes. If you are lightheaded, you may need to stay seated longer. When you feel better, you can leave.

A bit of blood may ooze from the vein beneath the skin. It will cause a bruise. Firm pressure over the site after the needle is removed will decrease the chance of a bruise. A bruise will usually fade in a day or 2.

Call your doctor right away if you have redness, swelling, lasting bleeding, or pain.

Results

Results can take a few days. Normal testosterone ranges differ by stage of development and gender.

Lower than normal total testosterone levels in males may be linked to:

• Problems making testosterone because of injury or health conditions that affect the testicles
• Undescended testicle(s)
• Alcohol use disorder
• Problems with the pituitary gland or hypothalamus in the brain
• Hypothalamic disease
• Testicular feminization—males who have female features
• Delayed puberty
• Kallman syndrome
• Klinefelter syndrome
• Prader-Willi syndrome
• Estrogen therapy

Higher than normal total testosterone levels may be linked to:

• Females:
  • Adrenal gland problems
  • Adrenal tumors
  • Anabolic steroid use
  • Ovarian tumors
  • Polycystic ovary syndrome
• Males:
  • Early puberty
  • Adrenal gland problems
  • Tumors in the testicles or adrenal gland
  • Anabolic steroid use

Your doctor will talk to you about the results. A test may point to an illness that you do not have. It can also miss an illness that you may have. The doctor will check your symptoms and all test results before making a diagnosis.