CPT® Code 84402

The CPT® Code 84402 refers to a laboratory test specifically designed to measure the levels of free testosterone in the blood. Free testosterone is the fraction of testosterone that is not bound to proteins in the blood, making it biologically active and available for use by the body's tissues. This test is crucial for assessing testosterone levels, which play a significant role in various physiological processes, including the promotion of protein synthesis and the growth of cells and tissues. Testosterone is an androgen hormone produced primarily in the testes of males, the ovaries of females, and the adrenal glands of both sexes. The measurement of free testosterone is often performed alongside other tests, such as the total testosterone test (CPT® Code 84403) and the sex hormone binding globulin test (CPT® Code 84270), to provide a comprehensive evaluation of an individual's hormonal status. The testing process involves obtaining a blood sample through venipuncture, which is a standard procedure in laboratory settings. The analysis of serum or plasma samples from adult males typically employs quantitative electrochemiluminescent immunoassay techniques, while alternative methods such as quantitative equilibrium dialysis combined with high-performance liquid chromatography-tandem mass spectrometry may also be utilized. For children and adult females, the testing is conducted using quantitative high-performance liquid chromatography-tandem mass spectrometry or electrochemiluminescent immunoassay, with results calculated based on a mathematical expression that incorporates sex hormone binding globulin levels.