CPT® Code 84410

The CPT® Code 84410 refers to a laboratory test specifically designed to measure bioavailable testosterone in serum. Testosterone is classified as an androgen hormone, which is produced by both males and females. In the bloodstream, the majority of testosterone is bound to a protein known as sex hormone binding globulin (SHBG), rendering it biologically inactive. However, testosterone that is free or bound to albumin is considered active and bioavailable, meaning it can exert physiological effects in the body. This test is particularly useful in diagnosing androgen deficiency in males, especially when total testosterone levels are at the lower limits of normal. Additionally, it can help identify alterations in SHBG levels that may occur due to factors such as aging, obesity, or the use of certain medications. In females, the test is valuable for diagnosing conditions associated with hyperandrogenism, including amenorrhea, hirsutism, polycystic ovarian syndrome (PCOS), and virilization. The procedure involves obtaining a blood sample through venipuncture, which is separately reportable. The measurement of serum concentration of free testosterone is achieved through a method known as differential precipitation, which involves the use of SHBG and ammonium sulfate after the serum specimen has been equilibrated with tracer amounts of tritium-labeled testosterone.