SHBG test: when it helps and which order to place

An SHBG test is for one situation: you want to know how much of your testosterone is tied up in a binding protein. Before you buy it, check whether another test answers your question.

For the plain definition, see what SHBG is. This page is about deciding whether to order the test.

SHBG

SHBG on its own, for when you already have a total testosterone result to pair it with or a clinician has asked for it.

$69

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Price checked October 2026. Not available in ND, RI, NY, NJ, MD and HI. We earn a commission on sales.

What the test measures

SHBG (sex hormone binding globulin) is a protein that attaches to testosterone and estrogen and helps control how much of each is active. The test measures SHBG in a blood sample (MedlinePlus). A total testosterone test cannot tell free testosterone from the part bound to proteins, which is why SHBG is often checked next to it.

When it helps

MedlinePlus says the test is usually ordered for symptoms of abnormal testosterone levels, especially when a total testosterone test did not explain them. For men, those symptoms include low sex drive, trouble getting an erection, fatigue or loss of muscle mass, and fertility problems.

The Endocrine Society’s guideline goes further. It says to measure free testosterone in men who have conditions that alter SHBG, and it lists conditions that lower SHBG (such as obesity and diabetes) and conditions that raise it (such as aging, HIV disease and cirrhosis) (Bhasin et al., 2018). It says to measure free testosterone by equilibrium dialysis, or else estimate it with a formula using total testosterone, SHBG and albumin.

Getting a free testosterone figure

The free and total test gives both numbers on one order.

If you already have a total testosterone result, adding SHBG lets you enter both in the free testosterone calculator. It turns the two results into an estimate, not a measurement, and assumes a typical albumin level unless you enter your own. The guideline accepts calculating free testosterone by formula when equilibrium dialysis is not available.

• Free and total testosteroneBoth numbers on one order $99 See this test at HealthLabs

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The free vs total testosterone guide explains how the two numbers differ.

How to prepare

MedlinePlus says you don’t need any special preparation for an SHBG test. The seller’s page for this test doesn’t state a fasting rule, so follow the instructions on your lab order. If you are pairing it with a testosterone test, ask which sample timing applies and see best time to test.

Tell the person drawing your blood about all medicines, vitamins and supplements. MedlinePlus says some hormone-containing medicines can change SHBG. Don’t stop any medicine unless your clinician says to.

What a result can and can’t tell you

Labs set their own ranges, so use the range printed on your report. MedlinePlus describes the general pattern:

• Low SHBG means more testosterone is likely free and available to your body.
• High SHBG means less is available to your tissues.

Both directions have many possible causes, from thyroid and liver conditions to medicines. See high SHBG for what is linked to a high result.

An SHBG result can’t diagnose low testosterone, and it can’t name its own cause. It is read together with testosterone and your symptoms. If a result is outside the range, take it to a clinician.