Serum/plasma concentration of testosterone (total)

Your doctor may order this test to measure the amount of testosterone in your blood. Testosterone is a hormone that plays an important role in muscle strength, bone health, mood, sex drive, and fertility in both men and women. This test can help find the cause of symptoms such as low energy, reduced sex drive, erectile dysfunction, irregular periods, or trouble getting pregnant, and it can also be used to monitor hormone therapy or treatment for certain medical conditions.

Doctors may order a total testosterone test to diagnose or monitor conditions such as low testosterone (hypogonadism), fertility issues, or symptoms of hormonal imbalances like polycystic ovary syndrome (PCOS) in women. It can also be used to evaluate symptoms like fatigue, low libido, or changes in body hair.

Before the test, your doctor will give you specific instructions to help make sure the results are accurate. The blood sample is usually taken in the morning, when testosterone levels are highest, so you may be asked to schedule an early appointment. You may need to avoid eating or drinking anything except water for several hours beforehand, and your doctor may ask you to pause certain medicines, such as steroids or hormone supplements, for a short time. Tell your doctor about all medicines, vitamins, and herbal products you take, and mention any recent illness, because these can affect your hormone levels.

No special preparation is usually needed, but you may be asked to avoid certain medications that could affect results, such as certain steroids or birth control pills. If you’re taking these, your doctor will advise you. For men, it’s often done after waking up in the morning, as testosterone levels can vary throughout the day.

This test is a simple blood draw that usually takes only a few minutes. A nurse or phlebotomist will wrap an elastic band around your upper arm to make the veins easier to see, clean your skin with an antiseptic, and insert a small needle into a vein, usually in your arm or hand. You may feel a quick pinch or slight sting when the needle goes in. A small tube will collect the blood, and then the needle is removed and gentle pressure is applied with a cotton ball or bandage. You can usually return to your normal activities right away.

A blood sample will be drawn from a vein, typically in your arm. You may feel a slight pinch when the needle is inserted, but the process usually takes a few minutes. You can resume normal activities immediately afterward.

Your results will show whether your testosterone level falls within the normal range for your age and sex. Levels that are higher or lower than normal can point to different conditions. Low testosterone in men may be linked to problems with the testicles or the pituitary gland, while high levels in women may be related to polycystic ovary syndrome or other hormonal issues. Keep in mind that normal ranges vary between labs, and factors like medicines, time of day, and overall health can affect the results. Your doctor will review your results with you and may recommend additional testing if needed.

Testosterone levels can vary based on age, sex, and health status. While reference ranges exist, they can differ slightly between labs. Your doctor will interpret your results in the context of your overall health, symptoms, and medical history. Abnormal results may prompt additional testing or follow-up.