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HIV Screening Test
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Lab Tests

HIV Screening Test

HIV tests detect the human immunodeficiency virus to enable early treatment and prevent the progression to AIDS.

Overview

An HIV test checks for infection with HIV, a virus that destroys immune system cells. HIV is the virus that causes AIDS (acquired immunodeficiency syndrome), the most serious stage of infection. While HIV is spread through contact with blood and other body fluids, it is manageable. Most people with HIV do not have AIDS, and early treatment can prevent the virus from destroying the immune system.

If you believe you were exposed to HIV, seek emergency treatment (PEP) within three days to potentially prevent infection.

Types of HIV Tests

  • HIV antibody tests: Detect disease-fighting proteins. These can be lab tests, rapid tests, or at-home kits. They may take 23 to 90 days after infection to show a positive result.
  • HIV antibody/antigen tests: The most common tests; they look for both antibodies and viral antigens. Lab tests can detect infection as soon as 18 to 45 days after exposure.
  • NAT tests (Nucleic Acid Tests): Detect the virus directly in the blood. These are the most sensitive tests, capable of finding HIV 10 to 33 days after infection, though they are primarily used for monitoring treatment rather than routine screening.

Why do I need an HIV test?

The CDC recommends that everyone aged 13 to 64 get tested at least once. You should be tested annually if you have a higher risk of infection, such as sharing needles, exchanging sex for money or drugs, or having a partner whose HIV status is unknown. Pregnant individuals are also tested, as treatment during pregnancy can significantly reduce the risk of passing the virus to the baby.

What happens during the test?

Samples can be collected via:

  • Blood from a vein: A professional draws blood using a needle.
  • Blood from a finger: A lancet is used to prick the finger.
  • Saliva: A swab is wiped along the gums.
  • Urine: A sample is collected in a container.

What do the results mean?

  • Negative: No signs of HIV were found. If you had a possible exposure within the last 90 days, you may need a follow-up test.
  • Positive: Signs of HIV were found. A follow-up test is required to confirm the diagnosis. If confirmed, starting antiretroviral therapy (ART) is essential to protect your health and reduce the amount of virus in your blood.

HIV testing can be performed anonymously, where you receive a number instead of using your name to obtain results.

Frequently Asked Questions

Yes, FDA-approved at-home HIV tests are available and highly accurate when used correctly. These kits typically collect a small blood sample via a finger prick and provide results in about 20 minutes. However, at-home tests are generally less sensitive than lab-based 4th-generation tests, meaning they have a longer window period (often up to 90 days). A positive result from an at-home test is a preliminary positive and requires confirmation with a follow-up lab test. A negative result is reliable only if the test was taken after the appropriate window period for that specific kit.
No, a positive HIV test means you are infected with the virus, but it does not mean you have AIDS. AIDS is the most advanced stage of HIV infection, defined by a very low CD4 cell count or the presence of certain opportunistic infections. Most people with HIV who receive timely treatment with antiretroviral therapy (ART) do not develop AIDS. After a positive screening result, you will undergo confirmatory testing. If confirmed, your provider will order additional tests, such as a CD4 count and viral load, to assess your immune health and determine the best treatment plan to keep the virus undetectable.
The window period is the time between an HIV exposure and when a test can accurately detect the infection. During this period, the virus is present in the body, but antibody levels or viral loads are too low for standard tests to identify. For example, antibody tests may take 23 to 90 days to turn positive, while 4th-generation antigen/antibody tests can detect infection in 18 to 45 days. If you test negative during this window, it is a false negative. You must retest after the full window period for the specific test used to confirm your status.
Post-Exposure Prophylaxis (PEP) is an emergency course of HIV medication taken to prevent infection after a potential exposure, such as a needle stick or unprotected sex. It is most effective when started as soon as possible, ideally within 2 hours of exposure, but it must be started within 72 hours (3 days) to be effective. PEP is not a treatment for existing HIV; it is a preventive measure. If you believe you have been exposed, seek emergency care immediately to assess the risk and begin medication if appropriate.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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