Testing for HIV

Part of HIV and Its Treatment

Terms Used in This Fact Sheet

HIV antibody test: An HIV test that checks for HIV antibodies in a person's blood, urine, or fluids from the mouth. HIV antibodies are a type of protein the body produces in response to HIV infection.

Mother-to-child transmission of HIV: The passing of HIV from a woman infected with HIV to her baby during pregnancy, during labor and delivery, or by breastfeeding.

Plasma HIV RNA test (viral load test): A test that measures the amount of HIV in the blood. This test is used to detect recent HIV infection or to measure viral load at any stage of HIV infection.

Rapid HIV antibody test: An HIV antibody test that can detect HIV antibodies in blood or oral fluids in less than 30 minutes.

Transmission of HIV: The spread of HIV from a person infected with HIV to another person through the infected person's blood, semen, genital fluids, or breast milk.

Unprotected sex: Sex without using a condom.

Viral load: The amount of HIV in the blood. One of the goals of antiretroviral therapy is to reduce viral load.

Western blot: A type of antibody test used to confirm a positive HIV antibody or plasma HIV RNA test.

Window period: The time period between a person's infection with HIV and the appearance of detectable HIV antibodies.

I may have been exposed to HIV. What should I do?

Get tested. The only way to know if you're infected with the virus is to get an HIV test.

Soon after infection with HIV, a person may have flu-like symptoms. But HIV infection isn't diagnosed on the basis of symptoms. Getting tested is the only way to know if you're infected with HIV.

What is the most common HIV test?

The most common HIV test is the HIV antibody test. HIV antibodies are a type of protein the body produces in response to HIV infection. The HIV antibody test checks for HIV antibodies in a person's blood, urine, or fluids from the mouth.

Generally it takes the body about 3 months from the time of infection to produce enough antibodies to be detected by an HIV antibody test. (For some people, it can take up to 6 months.) The time period between infection and the appearance of detectable HIV antibodies is called the window period. Because HIV antibodies are not detectable yet, the HIV antibody test isn't useful during the window period.

What HIV test is used during the window period?

The plasma HIV RNA test (also called a viral load test) can detect HIV in a person's blood within 9 days of infection, before the body develops detectable HIV antibodies. The plasma HIV RNA test is recommended when recent infection is very likely -- for example, soon after a person has had unprotected sex with a partner infected with HIV.

Detecting HIV at the earliest stage of infection lets people take steps right away to prevent transmission of HIV. (See the Preventing Transmission of HIV fact sheet.) This is important because immediately after infection the amount of HIV in the body is very high, increasing the risk of transmission of HIV. Starting treatment at this earliest stage of infection also can be considered.

What does it mean to test HIV positive?

A diagnosis of HIV is made on the basis of positive results from two HIV tests. The first test can be either an HIV antibody test (using blood, urine, or fluids from the mouth) or a plasma HIV RNA test (using blood). The second test (always using blood) is a different type of antibody test called a Western blot test. A positive Western blot test confirms that a person has HIV.

How long does it take to get HIV test results?

Results of the first antibody test are generally available within a few days. (Rapid HIV antibody tests can produce results within an hour.) Results of the plasma HIV RNA test and Western blot are available in a few days to a few weeks.

If I test HIV positive now, will I always test HIV positive?

Yes. There's no cure for HIV at this time. Because you will always be infected with the virus, you will always test HIV positive. But treatment with anti-HIV medications can help you live a longer, healthier life.

If a pregnant woman tests positive for HIV, will her baby be born with HIV?

In the United States and Europe, fewer than 2 babies in 100 born to mothers infected with HIV are infected with the virus. This is because anti-HIV medications given to women infected with HIV during pregnancy and delivery and to their babies after birth help prevent mother-to-child transmission of HIV. Another reason is that, in the United States and Europe, mothers infected with HIV do not breastfeed their babies. (For more information, see the HIV and Pregnancy fact sheet series.)

Where can I find information on HIV testing in my state?

Many hospitals, medical clinics, and community organizations offer HIV testing. To find an HIV testing site near you, contact AIDS_info_ for the number of your state AIDS hotline or visit http://www.hivtest.org/. You can also find information on testing locations on your state health department website.

For More Information

Contact an AIDS_info_ health information specialist at 1-800-448-0440 or visit http://aidsinfo.nih.gov. See your health care provider for medical advice.

This information is based on the U.S. Department of Health and Human Services' Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents.