National HIV Testing Day

National HIV Testing Day (NHTD) is an annual campaign to encourage people of all ages to “Take the Test, Take Control.”

Too many people don’t know they have HIV. In the United States, nearly 1.1 million people are living with HIV, and almost one in five don’t know they are infected. Getting tested is the first step to finding out if you have HIV. If you have HIV, getting medical care and taking medicines regularly helps you live a longer, healthier life and also lowers the chances of passing HIV on to others.

Types of HIV Tests

Antibody Tests: The most common HIV tests look for HIV antibodies in your body, rather than looking for HIV itself:

  • Enzyme immunoassay (EIA) tests use blood, oral fluid, or urine to detect HIV antibodies. Results for these tests can take up to two weeks.
  • Rapid HIV antibody tests also use blood, oral fluid, or urine to detect HIV antibodies. Results for these tests can take 10–20 minutes.

If you get a positive result from either of these tests, you will need to take another test, called a Western blot test, to confirm that result. It can take up to two weeks to confirm a positive result.

Antigen Tests
These tests are not as common as antibody tests, but they can be used to diagnose HIV infection earlier—from 1-3 weeks after you are first infected with HIV. Antigen tests require a blood sample.

PCR Test (Polymerase chain reaction test)
This test detects the genetic material of HIV itself, and can identify HIV in the blood within 2-3 weeks of infection.

Babies born to HIV-positive mothers are tested with a special PCR test, because their blood contains their mother’s HIV antibodies for several months. This means they would test HIV-positive on a standard antibody test—but a PCR test can determine whether the babies have HIV themselves.

For additional information, see CDC’s How HIV Tests work.