Testosterone blood test: what it measures and how to prepare
A testosterone blood test measures the amount of testosterone in your blood. Doctors use it, alongside your symptoms and other tests, to check whether your levels are in the expected range and to look for a cause if they’re not. This page explains what the test measures, how to prepare and how your results are read.
Why a doctor orders a testosterone test
A doctor may suggest the test if you have symptoms that could be linked to low testosterone, such as ongoing tiredness, lower interest in sex, low mood or changes in muscle and body fat. It’s also often part of a male fertility assessment. Read about low testosterone symptoms.
Total and free testosterone, in plain English
Most of the testosterone in your blood is attached to proteins, mainly one called sex hormone binding globulin (SHBG). A small amount isn’t attached, and that’s called free testosterone.
- Total testosterone measures all of it, attached and free. It’s usually the first test done.
- SHBG is often measured too, because it affects how much testosterone is available to the body.
- Free testosterone is usually calculated from your total testosterone and SHBG, and can help when the total result is borderline.
Getting an accurate result
- Have it in the morning. Testosterone is usually highest in the morning, so the test is generally done before about 10 am.
- Fasting. You may be asked to fast beforehand, because eating can temporarily lower the result. Follow the instructions on your pathology request.
- Timing around illness and sleep. If you’re unwell, or after a run of poor sleep or night shifts, it may be better to wait, because these can lower your result.
- Tell your doctor what you take. Some medicines and supplements can affect the result.
Why one result isn’t the whole picture
Testosterone levels vary from day to day, so a single low result is usually repeated before any conclusions are drawn. Your doctor also reads it alongside your symptoms and your other results.
Other tests often done at the same time
Depending on your symptoms, your doctor may check other hormones that control testosterone production, as well as your blood count, iron, thyroid function, blood sugar, cholesterol, and liver and kidney function. These help find a cause and give a picture of your general health.
Home test kits and pathology
Saliva and finger-prick kits are available, but their accuracy varies. Doctors generally rely on a blood sample taken at an accredited pathology collection centre, which is how testing works for a Nexus consultation.
Reading your results with a doctor
- Pathology. Arrange the blood test for your consultation through iMedical.
- Health assessment. Complete the online health assessment about your symptoms, health history and goals.
- Telehealth consultation. A registered medical practitioner calls you by phone and goes through your results and health assessment with you, in plain language.
- A plan, if appropriate. If treatment is clinically appropriate, your doctor will discuss the options and recommend a plan, with follow-up support. Your doctor may also suggest seeing your GP or a specialist where that’s more appropriate.
Your doctor decides what’s right for you, and a consultation doesn’t guarantee a prescription. Find out about the men’s hormone health and weight management consultation.
Frequently asked questions
Do I need to fast before a testosterone test?
You may be asked to. Follow the instructions on your pathology request, and ask the collection centre if you’re unsure.
What time of day should I have it?
Usually in the morning, generally before about 10 am, when levels are highest.
Can a testosterone test be wrong?
The test itself is reliable, but the result can be affected by the time of day, recent illness, poor sleep and some medicines. That’s why a low result is usually repeated.
Is testosterone checked in a normal blood test?
Not usually. It needs to be specifically requested by a doctor.
Is it covered by Medicare?
Medicare may cover testosterone testing when a doctor requests it for a clinical reason, so ask your GP. The pathology for a Nexus consultation is arranged privately through iMedical, so it isn’t billed to Medicare.
What happens after my results come back?
Your doctor goes through them with you in your telehealth consultation, explains what they show and talks through the next steps.
This page is general information only and isn’t a substitute for advice from your own doctor.
Clinical review
Clinically reviewed by Dr Built Varinporn Amporndanai. AHPRA registration number: MED0002175812.