The only way to know if you have HIV is to get tested
Types of tests used to test for HIV
An antigen/antibody test looks for both HIV antibodies and antigens. Antibodies are produced by your immune system when you’re exposed to viruses like HIV. Antigens are foreign substances that cause your immune system to activate. If you have HIV, an antigen called p24 is produced even before antibodies develop. Antigen/antibody tests are recommended for testing done in labs and are now common in the United States. This lab test involves drawing blood from a vein. There is also a rapid antigen/antibody test available that is done with a finger prick.
HIV antibody tests only look for antibodies to HIV in your blood or oral fluid. In general, antibody tests that use blood from a vein can detect HIV sooner after infection than tests done with blood from a finger prick or with oral fluid. Most rapid tests and the only currently approved HIV self-test are antibody tests.
A NAT looks for the actual virus in the blood and involves drawing blood from a vein. The test can either tell if a person has HIV or tell how much virus is present in the blood (known as an HIV viral load test). While a NAT can detect HIV sooner than other types of tests, this test is very expensive and not routinely used for screening individuals unless they recently had a high-risk exposure or a possible exposure and have early symptoms of HIV infection.
PCR stands for Polymerase Chain Reaction. This test looks directly for HIV in blood. It has the shortest potential window period and can be used from 3 days to 4 weeks after an exposure, PCR testing for HIV DNA is mainly used for babies born to HIV positive mothers. As a baby has the mother’s antibodies for the first 18 months, antibody testing is not used until a child is two years old.