HIV Testing

HIV attacks CD4 immune cells and, untreated, progresses over years to AIDS. That trajectory has changed completely: people diagnosed early and started on antiretroviral therapy have a life expectancy close to the general population, and someone with a sustained undetectable viral load cannot transmit the virus sexually — the finding summarised as U=U (undetectable equals untransmittable). The standard modern test is a 4th-generation antigen/antibody combination assay, which detects both the p24 viral antigen and antibodies, shortening the detection window compared with antibody-only tests. Rapid point-of-care versions return results in minutes; laboratory versions are typically same-day at a specialist clinic. Any reactive screening result is confirmed with a second, different assay before a diagnosis is made — screening tests are designed to over-call rather than miss, so a reactive screen is a signal to confirm, not a conclusion. Early HIV can present as a flu-like seroconversion illness a few weeks after exposure, or as nothing at all. Where a very recent high-risk exposure has occurred, post-exposure prophylaxis (PEP) is time-critical and should be discussed with a doctor within 72 hours; pre-exposure prophylaxis (PrEP) is the preventive option for ongoing risk.