eTopical Precious Finds
Testosterone testing can be confusing because a laboratory report may contain more than one measurement. Two of the most frequently discussed are total testosterone and free testosterone.
They are related, but they are not identical.
What Is Total Testosterone?
Total testosterone refers to testosterone circulating in the blood in both bound and unbound forms. Much of the testosterone in the bloodstream is attached to proteins, and total testosterone is commonly used as a starting measurement when a provider is evaluating possible testosterone deficiency.
What Is Free Testosterone?
Free testosterone refers to the smaller portion that is not bound to proteins. Because protein binding varies among individuals, there are clinical situations in which total testosterone and free testosterone may provide somewhat different information.
Patients researching total vs. free testosterone should resist the temptation to treat either number as a universal score of male health.
Testing Method Matters
The Endocrine Society recommends using accurate assays for total and free testosterone and applying appropriately derived reference ranges when interpreting results. Laboratories may use different ranges, so patients should discuss their specific results with the provider ordering the test.
Timing Also Matters
Testosterone levels fluctuate. MedlinePlus explains that testosterone blood testing is generally performed in the morning and that repeat testing may be needed to confirm a low result.
Numbers Need Symptoms
Even an accurately measured testosterone result is not the entire diagnosis. Current Endocrine Society guidance emphasizes compatible symptoms or signs together with consistently low testosterone.
Don’t Chase a Number
More testosterone is not automatically better. The useful question is whether a patient’s symptoms, history, and reliable laboratory results together support a diagnosis and, if so, which treatment approach makes sense.
Medical review: Adam Russell, PA-C, Hormone Balance Centers.
