HIVtesting

HIV testing is the process of determining whether a person is infected with the human immunodeficiency virus. Testing helps diagnose infection, guide treatment, and reduce onward transmission. Tests can be done in clinics, laboratories, community health centers, or at home in some settings, and options may be confidential or anonymous depending on the country or program.

There are several types of HIV tests. Antibody tests look for the antibodies the body makes in response to HIV and are common in rapid tests and standard laboratories. Fourth-generation tests detect both HIV antibodies and the p24 antigen, identifying infection earlier than antibody-only tests. RNA tests detect the virus itself and can identify infection very soon after exposure, but they are used less routinely and in specific clinical situations. Tests can use blood, oral fluid, or sometimes urine; some home testing kits are available with guidance on confirmatory testing if results are reactive.

Window periods and test accuracy vary by test type. Most people develop detectable antibodies within weeks to a few months after exposure. Fourth-generation tests identify many infections within about 2–6 weeks, and RNA tests can detect infection around 10 days after exposure. Because of the early window period, a nonreactive result soon after possible exposure does not completely rule out infection, and a confirmatory test is required for a reactive result.

Interpreting results involves counseling and typically a confirmatory test if initial screening is positive. Negative results are usually reliable after the window period, but testing should be repeated if recent exposure is suspected. Accessibility includes clinics, sexual health centers, community organizations, and some home testing options, with guidance on follow-up and care if positive. Regular testing is advised for individuals at risk, and pregnant people are commonly tested to prevent perinatal transmission. If exposure is recent, seeking medical advice promptly is important, as post-exposure measures may be available.