CPT® Code 84704

The CPT® Code 84704 refers to the measurement of free beta chain human chorionic gonadotropin (hCG) levels through a blood sample. Human chorionic gonadotropin is a glycoprotein that plays a crucial role in pregnancy, being secreted by the trophoblast cells of the placenta. This hormone consists of two subunits: the alpha hCG and the beta hCG. During pregnancy, both subunits are typically elevated in the bloodstream, serving as important indicators of the body's physiological changes. The free beta chain of hCG is particularly significant, as its elevated levels during the first trimester can serve as a specific and sensitive diagnostic marker for various conditions. These include gestational trophoblastic neoplasms, such as hydatidiform mole and choriocarcinoma, as well as chromosomal abnormalities like Down syndrome and trisomy 18, and developmental issues such as neural tube defects. The testing process for free beta chain hCG involves a two-step methodology that utilizes two high-affinity monoclonal antibodies within an immunoradiometric assay (IRMA) system, ensuring accurate measurement of this important biomarker.