CPT® Code 87380

Infectious agent antigen detection by immunoassay technique, (eg, enzyme immunoassay [EIA], enzyme-linked immunosorbent assay [ELISA], fluorescence immunoassay [FIA], immunochemiluminometric assay [IMCA]) qualitative or semiquantitative; hepatitis, delta agent

The CPT® Code 87380 refers to a laboratory test designed to detect the presence of the hepatitis delta agent antigen in a blood sample using various immunoassay techniques. This test is crucial for identifying the hepatitis D virus (HDV), which is a defective RNA virus that can only replicate in the presence of the hepatitis B virus (HBV). The hepatitis delta agent is not structurally related to the hepatitis A, B, or C viruses, making it unique in its pathology. The presence of HDV can lead to severe liver complications, particularly in individuals who are already infected with HBV, potentially resulting in conditions such as fulminant acute hepatitis, cirrhosis, and hepatocellular carcinoma. To perform this test, a blood sample is collected and either placed in a fixative or sent fresh to a laboratory for analysis. The immunoassay techniques utilized in this test include enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay (FIA), and immunochemiluminometric assay (IMCA). Each of these methods employs specific mechanisms to detect the antigen. For instance, EIA and ELISA work by binding the antigen to a specific antibody and then adding a secondary enzyme-labeled antibody, which produces a color change or fluorescence detectable through colorimetric reading. FIA, on the other hand, uses a fluorescent compound to identify the binding of the detection antibody to the antigen, while IMCA relies on chemiluminescent substances to quantify the antigen-antibody complex through light emission. The test can yield qualitative or semi-quantitative results, providing essential information for the diagnosis and management of hepatitis D infections.