Plasma Free Testosterone by Immunoassay (Screening)

Why This Test Matters

Free testosterone is important because it reflects the biologically active portion of testosterone that your body uses. Unlike total testosterone, free testosterone isn’t bound to proteins and is directly available to your cells. This can be particularly useful for diagnosing conditions like hypogonadism (low testosterone) or evaluating symptoms related to hormonal imbalances, such as irregular menstrual cycles or low libido.

How the Test Works

Your blood sample is analyzed using an immunoassay method, which detects the presence of free testosterone molecules in your plasma. This method is highly sensitive and specific, helping to accurately measure the concentration of free testosterone without interference from other substances.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in your arm. The blood is processed to separate the plasma (the liquid part containing hormones and other substances) from the blood cells. This plasma is then sent to the lab for testing.

What to Expect Before the Test

No special preparation is needed for this test. You may have some mild discomfort or bruising at the injection site, but this usually fades quickly. If you’re on certain medications that affect hormones, let your healthcare provider know before the test.