- Includes
- SHBG-bound, albumin-bound and free testosterone
- Timing
- Early morning, on two separate days
- AUA low-T cutoff
- Below 300 ng/dL
- Add free testosterone when
- SHBG is abnormal or the total is borderline
Why it is the starting test
Total testosterone is widely available, inexpensive and well standardized compared with direct free testosterone assays. Guidelines from the American Urological Association and the Endocrine Society both start the evaluation of low testosterone here.
Getting the timing right
- Draw it early in the morning, when levels are highest. MedlinePlus cites 7 to 10 a.m.
- Repeat it on a separate day; the AUA calls for two early-morning measurements before diagnosis.
- The Endocrine Society recommends fasting morning samples, since eating can lower testosterone.
- Avoid testing during an acute illness, after a night of very poor sleep or after unusually hard training.
- Tell your clinician about opioids, steroids, hormone products and supplements.
Reading the number
The AUA uses a total testosterone below 300 ng/dL as a reasonable cutoff for low testosterone, combined with symptoms. Labs print their own reference ranges, which differ slightly by method, so compare with the range on your report.
A single value just above or below the line is not definitive. The pattern across repeated morning tests, plus how you feel, carries more weight.
When total testosterone is not enough
Because total testosterone includes hormone tied up by SHBG, anything that shifts SHBG can mislead. Obesity and insulin resistance lower SHBG, which can make the total look low while free testosterone is closer to normal. Liver disease, hyperthyroidism and oral estrogen raise SHBG, which can hide a low free level behind a normal total.
In those cases the Endocrine Society recommends measuring free testosterone by an accurate method, such as equilibrium dialysis, or calculating it from total testosterone, SHBG and albumin.
Next steps after a low result
If two morning totals are low, guidelines recommend LH testing to find out whether the problem starts in the testes or the brain, plus prolactin in some cases. A blood count, and PSA in men over 40, are checked before any treatment. A HealifyMD clinician orders and interprets this sequence with you, and labs are priced separately from treatment.
Units and conversions
In the U.S., total testosterone is usually reported in ng/dL. Some labs and many international studies use nmol/L; multiplying nmol/L by about 28.8 gives ng/dL. Check the unit before comparing results from different reports, and keep copies of past results so trends are easy to see.
Total testosterone: common questions
Is total testosterone the same as free testosterone?
No. Total includes all testosterone in the blood; free is the small unbound fraction available to tissues.
Why do I need two tests?
Testosterone varies from day to day. Two low morning results make the diagnosis more reliable.
Can I test in the afternoon?
It is not ideal. Levels are lower later in the day, which can make a result look low when it is not.
Is 300 ng/dL a universal cutoff?
It is the AUA's practical threshold. Lab reference ranges vary, and symptoms are always part of the diagnosis.
Does an at-home finger-prick test count?
It can be a starting point, but guidelines are built on standard morning blood draws, and confirmatory testing may be needed.
Should I fast?
The Endocrine Society recommends fasting morning samples. Follow the instructions on your lab order.
Sources
We cite government agencies, professional societies and peer-reviewed research. See our editorial policy.
- Testosterone levels testMedlinePlus (U.S. National Library of Medicine)
- Evaluation and Management of Testosterone Deficiency guidelineAmerican Urological Association
- Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline (2018)Endocrine Society