To find out if testosterone levels are abnormal in a male or female patient. Measurement may help to explain why a male 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 female. In females it is used to investigate polycystic ovarian syndrome (PCOS). More recently it has been used to investigate the so-called Male Menopause, also referred to as andropause (a normal process in which testosterone level gradually decrease with age). Testosterone levels in females decrease during peri-menopause and post menopause and can exacerbate symptoms.
If you are male and your doctor thinks that you may be infertile or if you are unable to get or maintain an erection.
If you are a young male 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), are infertile, have no periods or if they are irregular, or experiencing peri-menopause symptoms.
A blood sample is taken by needle from a vein in the arm. Because testosterone levels 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).
No test preparation is needed
Testosterone is a steroid hormone (androgen) made by the testes and adrenal glands in males, and by the peripheral tissues, adrenal glands and ovaries in females.
In males, testosterone has a role in reproductive health, facial and body hair, muscle mass and sex drive. In females, testosterone levels are about one tenth of those in males. In combination with oestrogen, testosterone in females has a role in bone health, sex drive and reproductive health.
How is it used?
Testosterone testing is used to diagnose several conditions in males and females. These conditions include:
- delayed or early (precocious) puberty
- decreased sex drive
- erectile dysfunction
- excessive body hair, also called hirsutism
- ovarian tumours
- peri-menopause/menopause care
Males and Females
- adrenal tumours
- Hypothalamic and pituitary disorders
When is it requested?
In males, the testosterone is measured alongside 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 male 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 males, 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 females, 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 fall during peri-menopause and following menopause, and can contribute towards the symptoms experienced. 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 males and it is normal for testosterone levels to fall as males 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 males (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 young males is usually the cause of early puberty.
In females, increased testosterone levels can indicate polycystic ovary syndrome (PCOS) or an ovarian or adrenal gland tumour. Decreased levels may be seen during peri-menopause and following menopause.
Is there anything else I should know?
Alcohol and liver disease can decrease testosterone levels in males and increase levels in females. Drugs, including androgens and steroids, can also reduce testosterone levels. Prostate cancer responds to androgens, so males with advanced prostate cancer may receive drugs that lower testosterone levels. Females may receive drugs that lower testosterone levels if they have PCOS. If I have a low testosterone level, will taking supplemental testosterone help?
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 males with erectile dysfunction may have low testosterone, testosterone administration does not improve the symptoms in all cases. Testosterone treatment for females can improve some of the symptoms associated with peri-menopause and menopause. Your doctor will determine if this is the right therapy for you.
I am a female, so why do I need a testosterone test?
Female’s bodies also produce testosterone but in small amounts. It is needed for hormonal balance. 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.
Body hair and testosterone
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 males, for example, testosterone promotes hair growth in the abdomen and back while hair growth is suppressed in the scalp, leading to male pattern baldness.
In females, excessive growth of hair (hirsutism), which is dark and coarse, on the face, chest and back is primarily due to increased levels of testosterone.
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.
On This Site
Tests: FSH, LH, SHBG, DHEAS, Estradiol (see Estrogens), Dihydrotestosterone (DHT), Gonadotropin-releasing Hormone, Semen Analysis, Anti-Mullerian Hormone, Androstenedione
Conditions: Infertility, PCOS, Endocrine Syndromes, Testicular Cancer, Adrenal Insufficiency, Congenital Adrenal Hyperplasia, Menopause