Antigen/antibody tests conducted in a lab (as opposed to on-site rapid tests) are the most accurate types of HIV test with at least a 99% accuracy rate.
Types of HIV Tests
There are three types of HIV tests:
- Antibody tests: Most rapid HIV tests and home HIV tests look for antibodies against the virus in the blood or saliva. Blood tests of this kind can typically detect HIV sooner after infection than saliva tests. Rapid test results are available in 30 minutes or less. Home tests must be sent to a laboratory for processing.
- Antigen/antibody tests: These HIV tests look for antibodies against HIV as well as an antigen called p24, which is produced sooner than antibodies when an HIV infection occurs. This is the recommended method for laboratory testing. Antigen/antibody lab tests are common in the U.S. and are sometimes available as rapid tests.
- Nucleic acid tests (NAT): These tests check for the virus in the blood. NATs are the most expensive type of HIV test. They are usually only recommended for someone who has had a high-risk exposure or has early symptoms of HIV infection after a possible exposure.
HIV Test Accuracy
False positives are incredibly rare with any type of HIV test. When it comes to correct positive results, HIV tests received the followed accuracy ratings in a study that analyzed results from 21,234 HIV tests from 2003 to 2008:
- Antibody lab test: 95%.
- Antibody rapid test: 94.3%.
- Antigen/antibody lab test: 99.1%.
- Antigen/antibody rapid test: 96.6%.
This study did not include nucleic acid tests, which are not commonly used for HIV screening. These tests are considered to be the most accurate test option in the early stages of infection. Taking PrEP or PEP could reduce the accuracy of a NAT if you have HIV, so tell your medical provider if you are taking either of these medications before you get tested.