How effective is an HIV test for HIV infection?

Different tests look for HIV antibodies, the virus antigen, or genetic material. These markers appear at different points after exposure. A negative result soon after a possible exposure may need repeat testing after the test's window period. A reactive screening result is not the final diagnosis; a laboratory follow-up test is used to confirm it. Testing cannot show when infection occurred.

Tell the testing service when the possible exposure happened and which medicines you take. Follow the service's advice about the test type and repeat timing. If exposure was recent, seek urgent medical advice about post-exposure prevention rather than waiting for a test result. Until the result is clear, use condoms and do not share needles.

Seek prompt medical care after a recent possible exposure, especially if there was sexual contact without a barrier or shared injection equipment. Get help for fever, rash, sore throat, swollen glands, or flu-like illness after an exposure, while remembering these symptoms have many possible causes. Urgent care is needed for severe illness or difficulty breathing.

Ask which HIV test is being used, when it becomes reliable after your exposure, whether you need a repeat test, and whether other sexually transmitted infection tests or post-exposure prevention are appropriate.