What is the commonly used screening method for detection of HIV-1 antibodies?

• A. NAT
• B. PCR
• C. Enzyme-Linked Immunosorbent Assays
• D. Western blot

Answer: (C)

Screening for HIV-1 antibodies is typically done with an enzyme-linked immunosorbent assay. This test uses wells coated with HIV antigens. If a patient’s serum contains antibodies against HIV-1, those antibodies bind to the antigens. A secondary enzyme-labeled anti-human antibody then binds to the patient antibodies, and adding a substrate produces a color change that the instrument reads. The method is highly sensitive, scalable, and cost-effective, making it ideal for screening large numbers of samples quickly.

Because ELISA is designed to detect antibodies, a positive or uncertain result is usually followed by a confirmatory test to verify the specific antibody response. Western blot serves that confirmatory role by showing reactivity to multiple HIV antigens, but it is not used for initial screening due to being more labor-intensive and costly.

NAT and PCR detect viral nucleic acids rather than antibodies, so they’re used for different purposes (such as detecting acute infection or measuring viral load) rather than screening for HIV-1 antibodies.