Testosterone Test

A testosterone test is a simple blood test that measures the level of testosterone circulating in your bloodstream. Testosterone is a reproductive hormone primarily produced in the testes in men and the ovaries in women with small amounts also produced by the adrenal glands.

Since hormone levels naturally fluctuate throughout the day, the test is usually performed in the morning when testosterone levels are at their highest.

What Does Testosterone Do in the Body?

Testosterone is a key hormone that influences many physical and reproductive functions throughout life.

Functions in Men

In men, testosterone helps:

• Develop male reproductive organs during puberty
• Deepen the voice
• Increase muscle mass and strength
• Promote facial and body hair growth
• Support sperm production
• Maintain libido (sex drive)
• Help maintain bone density
• Support mood and energy levels

Low testosterone levels can affect fertility, sexual function, and overall wellbeing.

Functions in Women

Although women produce much smaller amounts of testosterone, it remains important for:

• Supporting libido
• Maintaining bone health
• Preserving muscle strength
• Contributing to mood and energy levels
• Supporting ovarian function

Abnormal testosterone levels in women may be associated with conditions such as polycystic ovary syndrome (PCOS).

Types of Testosterone Tests

Different types of testing may be used depending on your symptoms and medical history.

Total Testosterone Test

It is the most preferred type of test when it comes to measuring testosterone levels in the body since it measures the overall amount. This includes both testosterone that is attached to proteins and testosterone that circulates freely.

Since it provides a broader spectrum of testosterone levels, it is usually the first test recommended when symptoms like low libido, fatigue, erectile dysfunction, infertility or delayed puberty are to be investigated. In case of abnormal findings, further tests may be advised for better evaluation.

Free Testosterone Test

Most testosterone in the blood is attached to proteins which limits its immediate availability to the body’s tissues. A free testosterone test measures only the small percentage of testosterone that is not bound to proteins and can be readily used by the body.

This test may be helpful when symptoms of low or high testosterone are present despite normal total testosterone levels. It can provide additional insight into hormonal function, particularly in people with conditions that affect hormone-binding proteins.

Bioavailable Testosterone Test

Bioavailable testosterone refers to testosterone that is available in your body for use. It includes free testosterone as well as testosterone bound to a blood protein called albumin.

Bioavailable testosterone provides better insight into hormonal activity than the total testosterone test alone. Your doctor may suggest this test if they require more clarity on the amount of testosterone accessible to your body to support functions such as muscle maintenance, sexual health, energy levels and fertility.

SHBG Testing

SHBG, also known as Sex Hormone-Binding Globulin is a protein that binds with testosterone in the blood. A surplus or deficiency in this protein may result in alterations of testosterone levels in your tissues even when total testosterone levels appear normal.

For this reason, SHBG testing is sometimes performed alongside testosterone testing. Measuring SHBG can help doctors interpret testosterone results more accurately and identify hormonal imbalances that may not be obvious from testosterone levels alone. It is particularly useful in the evaluation of fertility concerns, metabolic conditions and certain endocrine disorders.

When Would I Need a Testosterone Test?

Testosterone plays different roles in men and women, so the reasons for testing often vary. In men, a testosterone test is most commonly recommended when symptoms suggest low testosterone levels which can affect their sexual health, energy, muscle mass and fertility.

Symptoms of Low Testosterone in Men

A low testosterone test may be recommended if you experience:

• Reduced sex drive
• Erectile dysfunction
• Difficulty achieving pregnancy
• Fatigue or low energy
• Decreased muscle mass
• Increased body fat
• Mood changes or irritability
• Poor concentration
• Reduced beard or body hair growth
• Low sperm count

Symptoms of High Testosterone in Women

In women, testing is often performed when symptoms point to high testosterone levels, as this may indicate hormonal conditions such as PCOS that can affect menstrual cycles, fertility and overall health. Common symptoms are

• Excessive facial or body hair growth
• Irregular or absent menstrual periods
• Acne
• Scalp hair thinning
• Deepening of the voice
• Difficulty conceiving
• Increased muscle mass

How Do I Prepare for a Testosterone Test?

There is no special preparation required and it simply involves a routine blood sample collected from a vein. However, your healthcare provider may advise you to:

• Schedule the test in the morning when the hormone levels are not diluted.
• Inform the laboratory about any medications or supplements you are taking because certain medicines can impact testosterone levels.
• Do not indulge in strenuous exercise before testing.
• Follow fasting instructions if recommended.