HIV Testing

An HIV test tells you if you have the human immunodeficiency virus (HIV). HIV is a sexually transmitted infection (STI) that attacks your immune system. In some people, HIV can lead to acquired immunodeficiency syndrome (AIDS), which can be life-threatening.

Depending on the test, you’ll provide a blood sample (from a vein or a finger prick) or an oral fluid sample that can be tested for HIV. Oral fluid contains cells from your mouth. It’s different from your spit.

Getting tested for HIV is important because the sooner you know about an infection, the sooner you can receive treatment. Everyone should get at least one HIV test in their lifetime. HIV tests are important because there are newer medications for both the person who is positive and their loved ones and sex partners who are negative.

Why and when should you get tested for HIV?

HIV doesn’t always cause symptoms in its early stages. An HIV test may be the only way to detect the virus and prevent spreading it to others. The U.S. Preventive Services Task Force recommends that everyone ages 15 to 65 get tested for HIV. You should also get tested if you’re at increased risk for HIV or if you’re pregnant.

HIV testing for high-risk groups

HIV gets transmitted through body fluids exchanged during vaginal and anal sex and through blood. You’re considered high-risk if it’s likely that you’ve been exposed to these fluids from a person who has HIV. It could be transmitted via unsafe needles or needle stick accidents.

You may need regular HIV tests if you:

• Have sex with a partner who has HIV
• Have a new sex partner or multiple sex partners whose HIV status you don’t know
• Are a sexually active man who has sex with other men (MSM)
• Have another STI or a partner who has an STI
• Share needles or syringes

Ask your healthcare provider about how often you should get tested if you’re at higher risk for HIV.

Testing during pregnancy

An HIV test is recommended during pregnancy, especially in the first trimester. Getting treatment early in pregnancy can prevent you from transmitting the virus to your newborn. If you’re pregnant and considered high risk, you should be retested again during your pregnancy.

Where can I get an HIV test?

You have many options for testing sites (including your own home).

• You can get tested in your healthcare provider’s office, a clinic or a community health center.
• The U.S. Centers for Disease Control and Prevention (CDC) allows you to type your address into a search bar and locate testing sites for HIV and other STIs. Many of these sites offer free testing.
• You can search STI testing locations using the HIV Testing Sites & Care Services Locator.
• You can purchase an at-home HIV test kit in stores or online if you’re 17 or older. The U.S. Food and Drug Administration (FDA) has approved two at-home HIV self-tests: OraQuick® HIV Self-Test and INSTI® HIV Self-Test.

How does an HIV test work?

An HIV test checks your blood or oral fluid for signs of HIV. If you test positive, you’ll need another test to confirm the result. If you test negative, you likely don’t have HIV. To trust the results, you’ll need to be sure that you took the test at the right time to detect the virus. It takes some time after you’ve been exposed to the virus for an HIV test to detect it.

What are the types of tests?

These are the main types of HIV tests:

• Nucleic acid (NAT) test: The NAT test can detect HIV RNA, the genetic material in HIV. The test can also tell how much of the virus is in your blood. For this type of test, a healthcare provider draws blood from a vein in your arm.
• Antigen/antibody test: Combination antigen/antibody tests check for signs of the virus instead of the virus itself. First, it tests for antigens. An antigen is a substance that triggers an immune response. If you have HIV, antigen p24 will be in your blood. The test also checks for HIV antibodies. Your immune system makes HIV antibodies to fight off the virus.
• Antibody tests: This test checks for HIV antibodies.

As the NAT test is more expensive, you’ll rarely take this test to screen for HIV unless you have symptoms. If you’re HIV-positive, your healthcare provider may order the NAT test to check your viral load, or how much of the virus is in your blood.

To screen for HIV, you’ll likely take an antibody test or a combination antigen/antibody test first. You’ll need follow-up testing if your results are positive to confirm the results.

What is the window period to detect HIV after exposure?

HIV tests can’t detect HIV immediately after you’ve been exposed. It takes time for your body to make antibodies in response to the virus. The window period is the time between HIV infection and when a test can reliably detect HIV. You’ll need to have an HIV test after the window period.

• A nucleic acid (NAT) test has the shortest window period. It can tell if you have an HIV infection from 10 to 33 days after exposure.
• Antigen/antibody tests can detect infection from 18 to 45 days after exposure (for blood draw tests) or 18 to 90 days after exposure (for finger-prick tests).
• Antibody tests (most rapid and at-home tests) can detect infection 23 to 90 days after exposure.

Remember that your test results won’t be accurate if you take the test too soon after exposure to HIV.

How do I prepare for the test?

You don't need to do anything to prepare for tests involving blood draws. You may need to avoid eating or drinking 30 minutes before taking at-home tests that use oral fluid. Follow the instructions on the kit.

What can I expect during the test?

It depends on which test you take and where you take it.

Lab HIV tests

Most HIV tests involve a healthcare professional drawing blood and sending it to a lab for analysis. These tests may take place in your provider’s office or a clinic. If you test positive, your provider will do additional testing to confirm the results.

The CDC recommends the following sequence of HIV tests:

• Test #1: An antigen/antibody test to check for HIV antigen p24 and HIV antibodies. If the result is reactive (positive), you’ll need a second test.
• Test #2: An antibody test to check for antibodies associated with HIV-1 and HIV-2. If this test is positive, you have HIV. If the result is negative or inconclusive, you’ll need a third test.
• Test #3: The NAT test to check for the genetic material of HIV in your blood.

Rapid HIV tests

Rapid HIV tests can check your blood or oral fluid for HIV antibodies. Some rapid tests also check for the p24 antigen. A healthcare professional may collect blood from a vein or with a finger prick. An oral fluid test uses a mouth swab.

Some rapid tests can provide results in as little as five minutes. Keep in mind that these results are preliminary. If your result is positive, you’ll need additional testing from a healthcare provider to know your HIV status.

At-home HIV tests

There are two FDA-approved tests you can take at home:

• OraQuick® checks oral fluid for HIV antibodies. You collect a sample by swabbing your upper and lower gums. You place the swab in a vial and read the result in about 20 to 40 minutes.
• INSTI® checks a small sample of blood from your fingertip for HIV antibodies. You collect the blood with a finger prick and add it to the test device. The result is available in about one minute.

If you test positive, you’ll need another test to confirm the results.

How long does it take to get HIV test results?

How quickly you receive the results depends on the type of test. Some rapid tests, like antigen/antibody and antibody tests, can give results in under 20 minutes. You may have to wait several days to get results from the NAT test.

What type of results do you get, and what do the results mean?

Test results will be negative or positive.

• A negative result means that the test didn’t detect signs of the virus. These results may mean that you don’t have HIV or that it’s too soon since your HIV exposure for the test to detect the virus.
• A positive result means that the test detected signs of the virus. These results may mean that you have HIV or that you’ll need additional testing to confirm results.

What happens if an HIV test is positive?

If you get a positive result on one test, you’ll want to do another test with your healthcare provider to be sure. Once your diagnosis is confirmed, you’ll work with your provider on a treatment plan. Your healthcare provider will determine how far HIV has progressed and recommend medicines to help you manage it. Treatment for HIV can help your body fight the virus and prevent AIDS. There are highly active anti-HIV medications that your provider will prescribe. They can also refer you to a specialist.

You’ll also want to talk about your diagnosis with your sexual partner(s). If you and your partner(s) have had unprotected sex, you could have transmitted the virus to them. They should get tested, too.

What does a negative result mean?

If your first test is negative and there’s a chance that you took the test too soon, take a second test after the window period has passed. The second test could confirm your negative result if you got tested before the infection was active in your body.

Even with a negative result, it’s important to protect yourself from HIV in the future. Use condoms or dental dams to reduce your risk of getting HIV and other STIs. If you’re at increased risk of HIV, you can take pre-exposure prophylaxis (PrEP). This is medicine that helps prevent HIV. Don’t share needles or other injection equipment.

How accurate are HIV tests?

The accuracy depends on the type of test and how soon after exposure you take it. Modern HIV tests are more than 99% accurate when used correctly and after the window period.

Can a normal blood test detect HIV?

HIV blood tests involve simple blood draws that are the same as most blood tests. What makes an HIV test different is how your blood gets tested at the lab. Your blood is checked specifically for signs of HIV, including antigens, antibodies or HIV RNA.

What is the difference between HIV-1 and HIV-2 tests?

There are two types of HIV: HIV-1 and HIV-2. Some antibody tests can detect HIV-1 or HIV-2 antibodies in your blood (or both). HIV-1 is the most common type of HIV. It also spreads more easily.