When a person goes for an HIV screening, they will give a blood or saliva sample for analysis. There are three main types of HIV tests healthcare professionals use. These are nucleic acid tests (NATs), antigen/antibody tests, and antibody tests.

No test can detect HIV immediately after transmission.

If a person is worried about having contracted HIV and thinks this may have happened within 72 hours, they can request post-exposure prophylaxis (PEP). This medicine is very effective at preventing HIV as long as a person takes it within 3 days of exposure.

Keep reading to learn more about the different types of HIV screening tests, why it is important to get tested, and what to expect following testing.

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HIV screening is the process of checking for the presence of HIV in the blood or other bodily fluids, such as saliva.

The screening can take place in a variety of settings, including a doctor’s office, a sexual health clinic, a community outreach center, and at home.

If a person is using a rapid test at home or an outreach center, they should arrange a laboratory test to confirm the result. This means they will need to go to a doctor’s office or laboratory where a healthcare professional will draw blood from their arm.

If a person’s initial test was a laboratory test, a doctor will usually order a second screening.

If a person wants to screen for HIV at home, they can use rapid self-tests or mail-in self-tests. These usually produce results within 20–30 minutes.

Some at-home testing kits require a person to swab around the gums, whereas others require a small amount of blood from a finger prick.

If a person is using a finger prick kit at home, they will need to mail the blood sample for analysis. An oral fluid test kit produces the result on-site.

Learn more about home HIV test kits here.

A person should always follow up a rapid test with a laboratory test that draws blood from the arm, to double-check the initial result.


NATs are the fastest laboratory test available.

In addition to detecting the actual virus, they can also indicate the viral load, which is the amount of the virus present in a person’s blood.

This type of test is not routine and is expensive. Doctors will only request a NAT if a person has very recently come into contact with HIV and is presenting with early symptoms. A person cannot do this test at home.

Antigen/antibody test

Antigen/antibody tests detect both HIV antigens and the antibodies that the immune system produces in response to the virus.

The HIV antigen is p24 and circulates throughout the body before the immune system produces antibodies.

This type of test is common in the United States. A person can also get an antigen/antibody test as a rapid testing kit, where they only need to prick their finger for the blood sample.

However, rapid testing kits may take longer to detect HIV — from 18 to 90 days after exposure — compared with laboratory tests that use blood from the arm, which can take 18–45 days after exposure.

HIV antibody tests

When a person’s immune system detects HIV, it begins to create antibodies to destroy the virus. Home rapid testing kits using either oral fluids or blood from a finger prick detect HIV antibodies.

That said, rapid testing kits detect HIV later than those that use blood from the arm. Therefore, a person with more recent exposure to HIV may want to take an antibody test at a doctor’s office or laboratory.

Learn more about rapid HIV tests here.

The Centers for Disease Control and Prevention (CDC) state that screening for HIV is of paramount importance, as 161, 800 people in the United States do not know they have HIV.

Moreover, up to 40% of new HIV cases occur because people are unaware that they are living with the virus.

The sooner a person knows they have HIV, the earlier they can receive treatment. This in turn could halt the virus’s progression into AIDS and eliminate transmission.

Learn more about the differences between HIV and AIDS here.

Anyone aged 13–64 years should receive screening for HIV at least once in their lives. If a person feels they engage in behavior that puts them at a higher risk, they should request screening more often.

A person should consider their risk if they are:

There are several ways a person can get HIV screening. These include:

  • asking a doctor for a test
  • requesting a rapid self-test online
  • buying a rapid self-test at a pharmacy
  • visiting a community outreach center or sexual health clinic

A person can also use this HIV service locator.

If a person receives an initial negative HIV result from an antibody test, they may still have HIV.

Sometimes, HIV antibodies take a while to present, which experts refer to as a window period. That is why additional testing is often necessary.

If the result comes back negative after the window period, a doctor is sure the person does not have HIV.

However, a person should still practice sex with a condom or other barrier method to ensure they do not contract HIV in the future.

A doctor will confirm a positive HIV status after receiving follow-up laboratory test results. Shortly after a person receives an HIV diagnosis, they must start antiretroviral therapy (ART).

If a doctor treats HIV quickly, the amount of virus in a person’s body may fall to undetectable levels. This means that they can stay healthy for many years and that the virus cannot transmit to other people.

It is important a person seeks out a counselor or mental health professional if the positive diagnosis is impacting their well-being.

HIV screenings are important. The sooner a person receives a diagnosis, the earlier they can begin ART.

If a doctor is able to treat HIV promptly, the virus may fall to an undetectable level. This means that a person can live a full and active life despite the HIV diagnosis and that the virus cannot transmit to anyone else.

A person can get an HIV test in many locations, such as a sexual health clinic, doctor’s office, or laboratory. They can also request a rapid testing kit they can use at home.