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What is a testosterone test?

A testosterone test checks the testosterone level in the blood. Doctors use this test to diagnose conditions responsible for excess or insufficient testosterone. Testosterone is a vital male hormone produced in the testes.

In puberty, testosterone accumulates in the muscles, triggers the growth of chest hair, causes the penis to grow and deepens the voice. Testosterone also helps boost sex drive and produce sperm throughout a man’s life.

Women also produce testosterone in the ovaries but smaller quantities. This hormone also helps to maintain different body functions, including hormone balance.

What does a testosterone test check for?

Testosterone gets transported through the blood in two ways:

  • Free- unattached to proteins
  • Attached to albumin and sex hormone-binding globulin (SHBG)

The total testosterone test is usually part of a screening test. This test measures the attached and free testosterone. Your doctor may check your free testosterone levels to diagnose certain health issues.

In men, a private testosterone test can determine the cause of sexual issues such as erectile dysfunction or reduced sex drive. If getting your partner pregnant is difficult, your doctor can order a testosterone test to check if the testosterone level in your blood is low.

Low blood testosterone levels may indicate problems with the pituitary gland or hypothalamus, which controls the amount of testosterone produced in the body.  

In women, the testosterone test can identify the cause of missing or no periods, the presence of male pattern hair growth like hair on the face or chest, and difficulty getting pregnant.

Doctors may use this test to diagnose polycystic ovary syndrome (PCOS), which increases testosterone levels. Testosterone can also cause difficulty in getting pregnant and irregular periods. The test is usually done during a thorough assessment for certain adrenal gland tumours.  

Why do I need a testosterone test?

Doctors order a testosterone test when high, or low testosterone symptoms are present. Common symptoms of low testosterone for men are:

  • Hair loss
  • Swollen breasts
  • Depression, trouble concentrating or fatigue
  • Weak bones or osteoporosis
  • Low sex drive
  • Loss of muscle mass
  • Difficulty in keeping or getting an erection

A low sperm count may also cause low testosterone levels. If you have a low sperm count, your order testosterone testing.

The symptoms of low testosterone level include:

  • Vaginal dryness
  • Low sex drive
  • Fertility issues
  • Weak bones or osteoporosis
  • Irregular or no periods

High testosterone levels in women may cause the following symptoms.

  • Deep voice
  • Oily or acne-prone skin
  • Hair loss on the head
  • Excess body or facial hair
  • Irregular or no periods
  • Dark patches on the skin
  • Enlarged clitoris

What happens during testosterone testing?

A testosterone test is a simple blood test, usually done early in the morning when the testosterone levels are highest. Your healthcare provider will draw blood from a vein in your finger or arm. Ensure you inform your doctor if you take any herbal or prescribed medications.

Testosterone levels vary daily and every hour, so if your test result shows a high or low testosterone level, you will need to repeat the test.

What does the test result mean?

Your testosterone test result will tell you if your testosterone level is low or high. Your age and gender will determine the normal testosterone level.

The normal testosterone levels for adult males include:

  • 19 – 49 years – 249 to 836 nanograms per decilitre (ng/dL)
  • 50 years and above – 193 to 740ng/dL

The normal range of testosterone in adult females includes:

  • 19 – 49 years – 8 to 48ng/dL
  • 50 years and above – 2 to 41ng/dL

Depending on the results, the following tests may be necessary.

  • 17-hydroxyprogesterone

This test detects congenital adrenal hyperplasia, a condition affecting hormone production.

  • Androstenedione (AD)

This test checks the functionality of the testicles, ovaries or adrenal glands.

  • Biopsy

In a biopsy, the doctor will collect a small testicular sample to check for cancerous cells.


It checks for tumours or problems in the adrenal glands.

  • Oestrogen

This measures the level of oestrogen and helps to diagnose menopause or infertility.

  • Luteinising hormone (LH) or follicle-stimulating hormone (FSH)

Checking the levels of these hormones aids the evaluation of puberty in girls and fertility in women.

  • Prolactin

This test helps diagnose the cause of missing periods, low sex drive, breast discharge and infertility in women.

You can get a testosterone test near me at Private Blood Tests London if you experience symptoms of high or low testosterone levels. Call us today on 020 7183 024 to schedule an appointment for testosterone testing.