CPT® Code 87391

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; HIV-2

The CPT® Code 87391 refers to the detection of the HIV-2 antigen using various immunoassay techniques. This procedure involves testing a blood or saliva sample to identify the presence of the human immunodeficiency virus type 2 (HIV-2) antigen. The immunoassay techniques utilized in this process include enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay (FIA), and immunochemiluminometric assay (IMCA). These methods are designed to detect even minute quantities of the HIV-2 antigen by employing specific antibodies that bind to the antigen in the sample. HIV-2 is a variant of the HIV virus that can lead to acquired immunodeficiency syndrome (AIDS), a condition characterized by the progressive failure of the immune system. The virus is primarily transmitted through sexual contact, but it can also be spread through unscreened blood transfusions, sharing of needles, and from mother to child during childbirth or breastfeeding. The testing process begins with the collection of a sample, which is then processed in a laboratory setting. The immunoassay techniques work by introducing a secondary enzyme-labeled antibody that binds to the antigen, resulting in a chromogenic reaction that produces a visible color change or fluorescence, indicating the presence of the HIV-2 antigen. The results can be reported as qualitative, indicating the presence or absence of the antigen, or semi-quantitative, providing a measure of the antigen concentration based on colorimetric readings. This code is specifically used for testing HIV-2, distinguishing it from other related codes that pertain to HIV-1 testing.