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HIV Tests: Home Kits, Rapid Tests and Lab Tests Compared

By Richard D. Porter, Patient Advocate Updated

Quick answer

There are three types of HIV test: antibody tests, antigen/antibody tests and nucleic acid tests (NAT). The CDC recommends antigen/antibody tests for lab testing, and says most rapid tests and self-tests are antibody tests. A NAT looks for the virus itself and can detect HIV earliest. Which test fits depends on how long ago the possible exposure was. If it was in the last 72 hours, go to urgent care or an ER now and ask about PEP; testing can come after.

The test you need

HIV: NAT (tests for the virus)Reliable by day 33

HIV: Antigen/antibody lab testReliable by day 45

HIV: Antibody test or self-testReliable by day 90

Too earlyMay detect; retest if negativeReliable

Counted from your most recent exposure. Source: CDC. Work out your own dates

Test
HIV antigen/antibody lab test (the type the CDC recommends for lab testing)
Sample
Blood from a vein. Rapid tests use a finger stick; some antibody tests and self-tests use oral fluid.
When
The CDC says an antigen/antibody lab test can usually detect HIV 18 to 45 days after exposure, a NAT 10 to 33 days, and an antibody test 23 to 90 days.
Results
The CDC says rapid antigen/antibody tests take 30 minutes or less and self-test results come within 20 minutes. STDCheck says its antigen/antibody lab test takes 1 to 2 business days.

If you are searching for an HIV test, you probably want to know which one to pick, how soon it will tell you something reliable, and where to get it. The answer depends mostly on time since the possible exposure.

What if I was exposed in the last 3 days?

Read this before anything else. The CDC says PEP (post-exposure prophylaxis) is medicine that prevents HIV after a possible exposure, that it must be started within 72 hours (3 days) of a recent possible exposure, and that it’s for emergency situations. Go to urgent care or an emergency room now, or contact a health care provider right away, and ask about PEP. Don’t wait for a test result. You can test afterwards.

What are the types of HIV test?

The CDC lists three:

  • Antibody tests look for antibodies to HIV in blood or oral fluid. The CDC says they can usually detect HIV 23 to 90 days after exposure.
  • Antigen/antibody tests look for both HIV antibodies and antigens. With blood from a vein in a lab, the CDC says they can usually detect HIV 18 to 45 days after exposure. A rapid version done with a finger stick can usually detect HIV 18 to 90 days after exposure.
  • Nucleic acid tests (NAT) look for the virus itself rather than antibodies. The CDC says a NAT can usually detect HIV 10 to 33 days after exposure.

Which HIV test should I get?

Think in terms of your timeline:

  • Within 72 hours of exposure: PEP first.
  • About 10 to 45 days after: a NAT or a lab antigen/antibody test gives you the earliest reliable answer. The CDC says antigen/antibody tests are recommended for lab testing and commonly used in the US.
  • 90 days or more after: an antibody test, including a home self-test, usually works.
  • No specific exposure, just routine screening: the CDC says everyone ages 13 to 64 should get tested at least once, and a lab antigen/antibody test is the type the CDC recommends for lab testing.

How do rapid HIV tests work?

“Rapid” describes how quickly you get the result, not how early the test can detect HIV. The CDC says a rapid antigen/antibody test with a finger stick takes 30 minutes or less, and a rapid antibody test usually uses finger-stick blood or oral fluid. Look at the numbers above: a rapid finger-stick antigen/antibody test is listed at 18 to 90 days, while a lab version is listed at 18 to 45 days. Fast result, longer window.

Can I test for HIV at home?

Yes. The CDC says an HIV self-test is an antibody test you can use at home or in private, with results in about 20 minutes. HIV.gov says you can buy one at a pharmacy or online. Because it is an antibody test, it fits the 23 to 90 day window, and the FDA says the approved oral-fluid test has a window of about three months. Our HIV home test kit guide covers accuracy in detail.

Where can I get an HIV test?

HIV.gov lists health care providers’ offices, health clinics and community health centers, sexual health clinics, local health departments, family planning clinics and pharmacies, among others. Its HIV Services Locator finds nearby testing by ZIP code or city. You can also order a lab test online. STDCheck says its antigen/antibody test is a blood test with results in 1 to 2 business days, and that its HIV RNA test, which looks for the virus’s genetic material, typically takes 2 to 4 business days. Use the CDC’s timing above to decide when to test, not a seller’s.

What does a negative result mean?

If you test after a possible exposure and get a negative result, the CDC says to get tested again after the window period for the test you took. If you test again after that window, have no possible exposure during that time, and the result is negative, the CDC says you do not have HIV.

What does a positive result mean?

A positive on a rapid or home test is not final. HIV.gov says you will need a second test from a health care provider to be sure of your status. If the follow-up is also positive, the CDC says that confirms HIV infection. Treatment is prescribed by a clinician, so see one promptly.

Get care now if

  • You may have been exposed to HIV in the last 72 hours. Go to urgent care or an emergency room now and ask about PEP. Don't wait for a test.
  • You tested positive on a home or rapid test. You need a follow-up test from a healthcare provider to confirm.
  • You are pregnant and haven't had an HIV test. The CDC says all pregnant women should be screened at the first prenatal visit.

Call 911 for a medical emergency. Otherwise, an urgent care clinic, sexual health clinic or your doctor can see you.

When to test

  1. Today, if you may have been exposed in the last 72 hoursGo to urgent care or an emergency room now and ask about PEP. The CDC says PEP must be started within 72 hours of a recent possible exposure. Care first, test later.
  2. 10 to 33 days after exposureA NAT can usually detect HIV by now, according to the CDC. It is ordered by a clinician or through a lab.
  3. 18 to 45 days after exposureAn antigen/antibody lab test with blood from a vein can usually detect HIV in this range.
  4. After 90 daysAntibody tests, including home self-tests, can usually detect HIV by day 90. If you tested earlier and it was negative, the CDC says to test again after the window period for the test you took.

Common questions

Which HIV test is best?

There isn't one best test, only the best match for your timing. For lab testing the CDC recommends antigen/antibody tests, and a NAT can detect HIV soonest. If you're past 90 days since the exposure, an antibody test, including a home self-test, can usually detect HIV.

Can HIV tests give wrong results?

A test taken before its window period ends can come back negative even if HIV is present. That is why the CDC says to test again after the window period for the test you took. A positive on a rapid or home test also needs a follow-up test to confirm.

Is HIV testing free?

Often it's low cost or free. HIV.gov says testing is generally covered by insurance, some testing sites and health departments may offer free tests without coverage, and some health departments or insurers offer free or low-cost self-tests. You can also order a free self-test through the CDC's Together Take Me Home initiative, subject to availability.

How often should I get tested?

The CDC says everyone ages 13 to 64 should be tested at least once, and anyone who shares injection drug equipment should be tested at least once a year. If you have ongoing risk, ask a clinician how often is right for you.

Next: HIV antigen/antibody lab test (the type the CDC recommends for lab testing).

Blood from a vein. Rapid tests use a finger stick; some antibody tests and self-tests use oral fluid.. The CDC says an antigen/antibody lab test can usually detect HIV 18 to 45 days after exposure, a NAT 10 to 33 days, and an antibody test 23 to 90 days.

Read next

Sources

This guide is general information written by a patient advocate using public health sources. It is not a diagnosis. Only a clinician or a lab test can tell you whether you have an infection. Read how we write and check our guides.