Formal Name
Testosterone
This article was last reviewed on
This article waslast modified on 1 November 2017.
At a Glance
Why Get Tested?

To find out if testosterone levels are abnormal in a male or female patient. Measurement may help to explain why a man has difficulty in getting an erect penis (erectile dysfunction), the inability of your partner to get pregnant (infertility), premature or delayed puberty, or masculine physical features if you are women. In a women it is used to investigate polycystic ovarian syndrome (PCOS). More recently it has been used to investigate the so-called Male Menopause.

When To Get Tested?

If you are man and your doctor thinks that you may be infertile or if you are unable to get or maintain an erection

If you are a boy with either early or delayed sexual maturity

If you are a female but have male traits, such as a low voice or excessive body hair (hirsutism), or are infertile or have no periods or if they are irregular

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

None

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you will be able to access your results online.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, gender, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Testosterone is a steroid hormone (androgen) made by the testes in males. The production of testosterone is stimulated and controlled by luteinising hormone (LH), which is manufactured in the pituitary gland.

In men, testosterone stimulates the enlargement of the penis, growth of body hair, muscle development, and a deepening voice. It is present in large amounts in boys during puberty and in men to regulate the sex drive and maintain muscle mass.

In women testosterone levels are about one tenth of those in men.  Testosterone is produced both in small amounts from the ovary and by conversion from other weak androgens in the body.

Testosterone is also produced by the adrenal glands in both men and women.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

Because testosterone levels in the male are highest in the morning and lowest in the late afternoon and evening your doctor may ask you to have your blood taken in the early morning (about 9am).

There is no preparation e.g. fasting required for this test.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

Accordion Title
Common Questions
  • How is it used?

    Testosterone testing is used to diagnose several conditions in men, women, and boys. These conditions include:

    Boys

    • delayed or early (precocious) puberty

    Men

    • decreased sex drive
    • erectile dysfunction  
    • infertility

    Women

    • infertility
    • excessive body hair, also called hirsutism
    • virilization
    • ovarian tumours

    Men and women

    • adrenal tumours
    • Hypothalamic and pituitary disorders

       

  • When is it requested?

    In boys, the testosterone is measured with the FSH and LH tests, if puberty is delayed or slow in developing. Although puberty begins at different times in different individuals, generally by the age of 10 years, there are hormonal and physical manifestations of the onset of puberty. A delay can occur if the testes do not produce enough testosterone or if the pituitary does not produce enough LH.

    The test may be performed if a young boy seems to be undergoing a very early (precocious) puberty with obvious secondary sex characteristics, such as an enlarged penis, development of muscle mass, deepening voice and growth of body hair.

    In men, the test may be performed when infertility is suspected or if the patient has a decreased sex drive or erectile dysfunction, which can result from low testosterone levels.

    In women, testosterone may be measured if a patient has irregular or no menstrual periods (amenorrhoea), is having difficulty getting pregnant, or appears to have masculine features, such as facial and body hair, male pattern baldness, and a low voice. Testosterone levels can rise because of tumours that develop in either the ovary or adrenal gland or because of other conditions, such as polycystic ovarian syndrome (PCOS).

  • What does the test result mean?

    There is great variability in testosterone levels in men and it is normal for testosterone levels to fall as men get older.

    In males, a low testosterone level may be due to hypothalamic or pituitary disease with reduced production of LH and FSH, or damage to the testes with reduced production of testosterone. Genetic diseases can cause decreased testosterone production in young men (Klinefelter’s, Kallman’s, and Prader-Willi syndromes) or testicular failure and infertility (as in myotonic dystrophy, a form of muscular dystrophy). A decreased testosterone level also can indicate impaired testosterone production because of acquired damage to the testes, such as alcoholism, physical injury, or viral diseases like mumps. Use of most anabolic steroids also causes a decrease in testosterone levels.

    Increased testosterone levels in males can indicate testicular tumours . Increased testosterone in boys is usually the cause of early puberty.

    In women, increased testosterone levels can indicate polycystic ovary syndrome (PCOS) or an ovarian or adrenal gland tumour.

  • Is there anything else I should know?

    Alcoholism and liver disease in males can decrease testosterone levels. Drugs, including androgens and steroids, can also reduce testosterone levels. Prostate cancer responds to androgens, so men with advanced prostate cancer may receive drugs that lower testosterone levels.

  • If I have a low testosterone level, will taking supplemental testosterone help?

    Maybe. Testosterone supplements, either with patches or injections, can raise testosterone levels. However although men with erectile dysfunction may have low testosterone, testosterone administration does not improve the symptoms in all cases. Your doctor will determine if this is the right therapy for you.

  • I am a woman, so why do I need a testosterone test?

    Women’s bodies also produce testosterone but in small amounts. It is needed for hormonal balance and to help women’s bodies to function normally. If your body is producing too much testosterone, however, you may have more body hair than average, have abnormal or no menstrual periods, or be infertile. A testosterone test, together with other tests, can help your doctor to understand what is causing your symptoms.

  • Is the amount of body hair directly proportional to the amount of testosterone in my body?

    Studies have shown a proportional relationship of testosterone levels to the amount of body hair. However, the hair growth response to testosterone differs in different parts of the body. Hence, in some men, for example, testosterone promotes hair growth in the abdomen and back while hair growth is suppressed in the scalp, leading to male pattern baldness.

  • What are free and bioavailable testosterone?

    Most of the testosterone in the blood circulates bound to two main proteins, albumin and sex hormone binding globulin (SHBG). Only a small amount of testosterone (1-4%) is not bound and is  ‘free’.  The free testosterone is available to tissues.  Testosterone is loosely bound to albumin and this proportion may also be available to tissues.  Both free and bioavailable testosterone provide a measure of the amount of testosterone available to tissues and they give the same information.  Free testosterone is calculated from the testosterone and SHBG results whereas bioavailable testosterone is a separate measurement.

    The amount of free and bioavailable testosterone is affected by the levels of SHBG.  High levels of SHBG are caused by cirrhosis of the liver, anti-convulsant therapy, oestrogen therapy and hyperthyroidism.  Low levels are present in hypothyroidism, androgen use, nephritic syndrome, polycystic ovarian syndrome and obesity.  In these situations the measurement of free or bioavailable testosterone may be more helpful in diagnosis.