Testosterone

Definition

A testosterone test measures the amount of the male hormone, testosterone, in the blood. Both men and women produce this hormone.

The test described in this article measures the total amount of testosterone in the blood. Much of the testosterone in the blood is bound to a protein called sex hormone binding globulin (SHBG). Another blood test can measure the "free" testosterone. However, this type of test is often not very accurate.

Alternative Names

Serum testosterone

How the Test is Performed

A blood sample is taken from a vein. The best time for the blood sample to be taken is between 7 a.m. and 10 a.m. A second sample is often needed to confirm a result that is lower than expected.

How to Prepare for the Test

The health care provider may advise you to stop taking medicines that may affect the test.

How the Test will Feel

You may feel a slight prick or sting when the needle is inserted. There may be some throbbing afterward.

Why the Test is Performed

This test may be done if you have symptoms of abnormal male hormone (androgen) production.

In males, the testicles produce most of the testosterone in the body. Levels are most often checked to evaluate signs of abnormal testosterone such as:

In females, the ovaries produce most of the testosterone. The adrenal glands can also produce too much of other androgens that are converted to testosterone. Levels are most often checked to evaluate signs of higher testosterone levels, such as:

Normal Results

Normal measurements for these tests:

The examples above are common measurements for results for these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different specimens. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

Certain health conditions, medicines, or injury can lead to low testosterone. Testosterone level also naturally drops with age. Low testosterone can affect sex drive, mood, and muscle mass in men.

Decreased total testosterone may be due to:

Increased total testosterone level may be due to:

References

Rey RA, Josso N. Diagnosis and treatment of disorders of sexual development. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 119.

Rosenfield RL, Barnes RB, Ehrmann DA. Hyperandrogenism, hirsutism, and polycystic ovary syndrome. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 133.

Swerdloff RS, Wang C. The testis and male hypogonadism, infertility, and sexual dysfunction. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 221.


Review Date: 2/1/2022
Reviewed By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
© 1997- adam.comAll rights reserved.