Modern HIV tests are extremely accurate, but precise accuracy all depends on how long after HIV exposure you get tested and what kind of test you’re using. Generally, HIV tests after the three-month window are more than 99.97% accurate. However, no HIV tests can tell if you’re infected if you get tested immediately after exposure.
The three main tests for HIV include:
- Nucleic acid tests, which involve drawing the blood to see if the virus is present. It can be done in a clinic or doctor’s office and predicts HIV infection about one to four weeks after exposure.
- Antigen/antibody test, which tests the blood to see if there are any antibodies (substances produced by your immune system as a reaction to HIV) or antigens (substances produced by HIV that stimulate your immune system) in your blood. These tests can be done at a doctor’s office or clinic and offer rapid results. Vein blood tests are more accurate than finger prick blood tests and can detect HIV three to five weeks after exposure.
- Antibody test, which just looks for antibodies in your blood or saliva. These tests are common at clinics, but there are also home versions you can use to test yourself. These can start to predict HIV infection about three weeks to three months after exposure.
Keep in mind that some of these tests may show negative results if you get them done too early. This does not mean the test isn’t accurate, but rather, it might be the disease is just not detectable yet. That’s why medical professionals recommend getting tested again in 45 days if you had an antigen/antibody test done or in 90 days for nucleic acid or antibody tests.