What is the primary laboratory method used for detecting HIV infection?

The primary laboratory method used for detecting HIV infection is the ELISA test, which stands for Enzyme-Linked Immunosorbent Assay. This method is widely utilized due to its high sensitivity and ability to screen large numbers of samples simultaneously. The ELISA test works by detecting antibodies that the immune system produces in response to the HIV virus. When a person becomes infected with HIV, antibodies usually develop within a few weeks, making the ELISA test effective for early detection.

The assay utilizes specific antigens that are attached to a solid surface. When a sample containing HIV antibodies (if present) is added, it will bind to the antigen. A secondary enzyme-linked antibody that targets human antibodies is then added, and a substrate is introduced to produce a measurable color change. The intensity of the color corresponds to the amount of antibody present, allowing for quantification of the infection level.

While rapid antigen tests are also effective for detecting HIV and provide results quickly, they are more often used for screening in point-of-care settings rather than as the primary laboratory method. Immunofluorescence assays are generally more specialized and not as commonly used for initial screening compared to the ELISA. A complete blood count (CBC) test does not specifically detect HIV infection;