HIV Screening Test
Reviewed
An HIV screening test checks a sample of your blood, saliva, or urine to see if you are infected with HIV. It looks for antibodies (proteins your immune system makes to fight HIV) or antigens (parts of the virus itself). No test can find HIV immediately after infection; it takes weeks for signs of HIV to increase enough to show up on a test. If you think you were exposed, talk with your provider right away about emergency treatment called PEP, which may prevent infection if started within 3 days.
Preparation and collection
You don't need any special preparations. If you are getting tested in a clinic, you may want to write down any questions ahead of time.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- No test can find HIV immediately after infection. The window period depends on the test type and your body's response.
- A negative result does not always mean you don't have HIV—you may need a later test.
- A positive screening result requires a follow-up test to confirm an HIV diagnosis (unless a NAT test was used).
- At-home tests require careful following of instructions; results should be discussed with a provider.
What to do next
Discuss your results with your health care provider or an HIV counselor. They can explain what your result means and whether you need additional testing. If you have HIV, starting treatment early can protect your health and reduce the risk of spreading HIV to others.