HIV Overview

Testing for HIV (human immunodeficiency virus) determines if a person has acquired HIV. HIV is the virus that causes acquired immunodeficiency syndrome (AIDS). AIDS is the most advanced stage of HIV infection.

HIV testing can detect if you have HIV, but it cannot tell how long you have had HIV or if you have AIDS.

There are two reasons why HIV testing is important:

First, an estimated 15% of people with HIV in the United States are unaware they have HIV, and it is estimated that 40% of new diagnoses of HIV are transmitted by those who are not aware of their HIV diagnosis. Knowing your HIV status can help keep you—and others—safe. 

Second, early identification of HIV is important to reduce related illnesses and improve mortality because you can get HIV treatment sooner. Early and sustained treatment will help you live a long, healthy life.

If you are HIV negative:

A negative HIV test result shows that you do not have HIV. If you are at risk, you need to continue taking steps to avoid getting HIV, such as using condoms during sex. People at risk for HIV are typically in an environment or situation where HIV is common. Examples of at-risk individuals include:

• People who have unprotected sex with multiple partners.
• Healthcare workers who may come in contact with bodily fluids.
• People who travel to areas where HIV is common (such as sub-Saharan Africa). 

If you are at high risk of getting HIV, taking medicines to prevent HIV (called pre-exposure prophylaxis or PrEP). High-risk individuals are typically engaging in activities that are known to cause HIV. Examples of high-risk individuals include:

• Men who have sex with men.
• People who inject drugs, specifically those who share needles.
• People who have regular unprotected sex with strangers (such as sex workers).

For more information, read the HIVinfo fact sheets on The Basics of HIV Prevention and Pre-Exposure Prophylaxis.

If you are HIV positive:

A positive HIV test result shows that you have HIV, but you can still take steps to protect your health and the health of your partners. Begin by talking to your health care provider about antiretroviral therapy (ART). People on ART take a combination of oral HIV medicines (pills) every day to treat HIV infection. In some cases, doctors prescribe long-acting injections to treat people with HIV. The shots are given by health care providers and require routine office visits. HIV treatment shots are given once a month or once every other month, depending on the treatment plan. ART is recommended for everyone who has HIV, and people with HIV should start ART as soon as possible. ART cannot cure HIV, but HIV medicines help people with HIV live long, healthy lives.

A main goal of ART is to reduce a person’s viral load to an undetectable level. An undetectable viral load means that the level of HIV in the blood is too low to be detected by a viral load test. People with HIV who maintain an undetectable viral load have effectively no risk of transmitting HIV to their HIV-negative partner through sex.

The Centers for Disease Control and Prevention (CDC) recommends that everyone 13 to 64 years of age get tested for HIV at least once as part of routine health care. Generally, people at higher risk for HIV should get tested each year. Sexually active gay and bisexual men may benefit from getting tested more often, such as every 3 to 6 months. If you are over 64 years of age and at risk, your health care provider may recommend HIV testing.

Factors that increase the risk of HIV include:

• Having vaginal or anal sex with someone who is HIV positive or whose HIV status you do not know.
• Injecting drugs and sharing needles, syringes, or other drug equipment with others.
• Exchanging sex for money or drugs.
• Having a sexually transmitted disease (STD), such as syphilis.
• Having sex with anyone who has any of the HIV risk factors listed above.

Talk to your health care provider about your risk for HIV and how often you should get tested for HIV.

CDC recommends that all pregnant people get tested for HIV so that they can begin taking HIV medicines if they test positive. Pregnant people with HIV take HIV medicines during pregnancy and childbirth to reduce the risk of perinatal transmission of HIV and for their own health. For more information, read the HIVinfo fact sheet on Preventing Perinatal Transmission of HIV.

There are three types of tests used to diagnose HIV infection: antibody tests, antigen/antibody tests, and nucleic acid tests (NATs). HIV antibodies are disease-fighting proteins that the body produces in response to HIV infection. NATs look for the virus in blood. Your health care provider can determine the appropriate HIV test for you.  How soon each test can detect HIV infection differs, because each test has a different window period. The window period is the time between when a person may have been exposed to HIV and when a test can accurately detect HIV infection.

• Antibody tests check for HIV antibodies in blood or oral fluid. Most rapid tests and home use self-tests are antibody tests. Generally, antibody tests that use blood from a vein can detect HIV sooner than tests done with blood from a finger stick or with oral fluid.
• Antigen/antibody tests can detect both HIV antibodies and HIV antigens (a protein of the virus) in the blood and are the most used HIV tests. After HIV exposure, antigens will show up in the blood of a recently exposed person sooner than antibodies.
• NATs look for HIV in the blood taken from a vein. These tests may also be called "viral load tests" because they not only detect the virus but also determine the quantity of virus present in the blood. They can usually find HIV as soon as 10 to 33 days after infection. They are mostly used for monitoring HIV treatment and not for routine screening because they are expensive.

A person’s initial HIV test will usually be either an antibody test or an antigen/antibody test. NATs are not routinely used for HIV screening unless the person had a high-risk exposure or a possible exposure with early symptoms of HIV infection.

When an HIV test is positive, a follow-up test will be conducted for confirmation.  Sometimes people will need to visit a health care provider to take a follow-up test using another blood sample. Other times, the follow-up test may be performed in a lab using the original blood sample to ensure that the first positive result wasn’t a false positive.

Talk to your health care provider who will determine your HIV risk factors and the best type of HIV test for you.

HIV testing can be confidential or anonymous. 

Confidential testing means that your HIV test results will include your name and other identifying information, and the results will be included in your medical record. HIV-positive test results will be reported to local or state health departments to be counted in statistical reports. Health departments remove all personal information (including names and addresses) from HIV test results before sharing the information with CDC. CDC uses this information for reporting purposes and does not share this information with any other organizations, including insurance companies.

Anonymous testing means you do not have to give your name when you take an HIV test. When you take the test, you receive a number. To get your HIV test results, you give the number instead of your name.

Your health care provider can give you an HIV test. If you feel apprehensive about talking to your personal physician or family doctor, HIV testing is also available at many hospitals, medical clinics, substance use programs, and community health centers. Use CDC's GetTested treatment locator to find an HIV testing location near you. Getting tested through a professional health care provider is recommended; however, there are HIV self-testing kits available. Rapid self-test and mail-in self-test are the two types of HIV self-tests, but state laws regarding self-testing may limit their availability in some locations. 

A rapid self-test is an oral fluid (not the same as saliva) test done entirely at home or in private. There is currently one U.S. Food and Drug Administration (FDA)-approved rapid self-test called OraQuick In-Home HIV test (PDF). For more information, read the FDA’s Facts About In-Home HIV Testing.

A mail-in self-test requires a person to provide a blood sample from a fingerstick, which is then sent to a lab for testing.  

From CDC:

• Getting Tested for HIV
• Self-Testing

From FDA:

• OraQuick In-Home HIV Test

• Facts About In-Home HIV Testing

From the National Library of Medicine:

• HIV Testing

Also see the HIV Source collection of HIV links and resources.