How to Read Your Testosterone Test Results: Total, Free, and SHBG Explained

You've had your testosterone tested and the results are back. The lab report has a few numbers, possibly with units you don't recognise, and a reference range that may or may not flag your result as normal. This guide explains what each number means, how to read the ranges, and the questions worth asking your doctor before any decisions are made.

If you haven't been tested yet, our guide to getting a testosterone test in Singapore covers where, how, and how much.

The three numbers that matter most

A standard testosterone panel reports three values:

Total testosterone is the total amount of testosterone in your blood, including both bound and unbound. This is the headline number on most basic test panels.

Free testosterone is the small fraction — typically 1–2% of total testosterone — that is not bound to proteins and is biologically active. Tissues can only use free testosterone, which is why this number matters when total testosterone is borderline.

Sex hormone-binding globulin (SHBG) is the protein that binds most circulating testosterone. SHBG levels change with age, weight, thyroid function, alcohol use, and some medications. When SHBG is high (more common with age), more of your total testosterone is bound and less is biologically available. When SHBG is low (more common with obesity or insulin resistance), more is free.

Some panels also include LH and FSH — the pituitary hormones that tell the testes to produce testosterone. These help your doctor work out where in the system a problem originates.

Reference ranges for adult men

Reference ranges vary slightly between labs and across countries, but the broad consensus for adult men is roughly:

• Total testosterone: approximately 12–30 nmol/L (or 350–1,000 ng/dL in some labs). Anything above roughly 12 nmol/L (~350 ng/dL) is generally considered normal.
• Borderline: roughly 8–12 nmol/L (~230–350 ng/dL). This is the grey zone where symptoms and free testosterone matter.
• Low: below approximately 8 nmol/L (~230 ng/dL). This is generally considered clinically low.
• Free testosterone: typical adult male range is roughly 200–600 pmol/L (or 5–20 ng/dL), with substantial variation between labs.
• SHBG: typical adult male range is roughly 10–60 nmol/L.

If your lab uses different units or a different reference range, use the range printed on your report — it is calibrated for that lab's assay. The thresholds above are a general guide, not an authoritative cut-off for every laboratory.

What "normal" actually means

A testosterone result needs to be read in two dimensions, not one.

The number itself. Is total testosterone above, below, or within the laboratory's reference range? If borderline, what is free testosterone telling you?

The clinical picture. Do you have symptoms consistent with low testosterone? Endocrine Society guidelines emphasise that the diagnosis of hypogonadism requires both a low result and consistent symptoms. A low number without symptoms, or symptoms without a low number, do not by themselves make a diagnosis.

This is why two men with the same total testosterone of, say, 10 nmol/L can end up with very different clinical decisions. One has clear symptoms, low free testosterone, and other supportive findings; treatment may be appropriate. The other feels fine, has high SHBG explaining the relatively low total, and good free testosterone; no treatment is needed.

Why a single result isn't enough

Testosterone fluctuates day to day. Sleep loss, recent illness, intense exercise, stress, and the time of day all influence the result. Major clinical guidelines (Endocrine Society 2018; AUA 2018, updated 2023) recommend that any clinically significant low result be confirmed with a repeat test on a separate morning before any treatment decision is made.

If your test was drawn in the afternoon, or you'd had less than five hours of sleep, or you'd recently been ill, the repeat is even more important. A second test is not a delay tactic — it's the standard of care.

Other tests that might be ordered alongside

If your testosterone is low, your doctor will often want a broader picture before discussing treatment. Common additional tests include:

• LH and FSH to determine whether the issue is primary (testicular) or secondary (pituitary/hypothalamic)
• Prolactin to rule out a pituitary cause
• Thyroid function (TSH) because thyroid disease can mimic or worsen low-testosterone symptoms
• A full blood count (FBC) as a baseline before any potential testosterone treatment
• PSA in men over a certain age before considering TRT
• Glucose / HbA1c because metabolic factors and low testosterone often coexist

If your doctor orders these, it is usually because the result will change what they recommend.

Questions worth asking your doctor

When you sit down to discuss your results, useful questions include:

• Where does my result fall — normal, borderline, or low?
• Given my symptoms, what does this number actually mean for me?
• Do we need a repeat test before any decisions?
• Are there other tests you'd want to run alongside?
• If my testosterone is low, what reversible causes should we look at first?
• If we discuss treatment, what are the options and what are the trade-offs?

A good consultation leaves you understanding both the result and the next step.

Frequently asked questions

My total testosterone is 10 nmol/L — is that low?

10 nmol/L sits in the borderline range. Whether it is clinically meaningful depends on your symptoms, your free testosterone level, and what is happening with SHBG. This is a result worth discussing with a doctor rather than self-interpreting.

What's the difference between nmol/L and ng/dL?

They are different units for the same measurement. Singapore labs typically report in nmol/L; some international labs use ng/dL. To convert, multiply nmol/L by approximately 28.85 to get ng/dL (so 10 nmol/L ≈ 288 ng/dL).

Can I just look at free testosterone and ignore the rest?

Free testosterone is informative but is also harder to measure accurately than total testosterone. Some labs use a direct assay; others calculate free testosterone from total testosterone and SHBG. The numbers are usually interpreted together, not in isolation.

My result is in the normal range but I still have symptoms. What now?

A normal testosterone with persistent symptoms usually points your doctor to look at other causes — thyroid issues, sleep disorders, depression, medication side effects, vitamin deficiencies, or other endocrine conditions. The symptoms are real; the cause may just not be testosterone.

Should I get tested every year?

Routine annual testosterone testing in men without symptoms is not generally recommended. If you have a borderline result and your doctor wants to monitor change over time, periodic retesting is reasonable. If you're starting or on treatment, regular monitoring is part of standard care.

Discuss your results with a doctor on Noah

If you have a testosterone result you'd like help interpreting, you can book a confidential consultation with a Singapore-licensed doctor on Noah. Bring your lab report; a clinician can review the numbers in context and discuss what, if anything, to do next.