HIV Testing FAQs

Why is the HIV ELISA test reported as non-reactive if it is ‘negative’?

A non-reactive result means that no HIV antibodies were found. This would find any exposures which happened 6 weeks prior to test or before that. A non-reactive test does not mean that a person is immune to HIV in the future only that they do not show the virus in their body at the time of the test.

A negative HIV test means that no signs of HIV infection were detected. However, the implications of a negative HIV test depend on the sensitivity of the test performed, as well as the time elapsed between testing and possible exposure to HIV.

What is the p24 antigen and HIV 1&2 ELISA test?

  • HIV antigen tests look for the presence of HIV virus.
  • HIV antibody tests look for the presence of HIV antibodies.

After infection with HIV,

  • It takes about two weeks for the virus to replicate and produce enough antigen to be detectable
  • It takes more than three weeks for the body to produce sufficient antibodies to be detectable through testing.

So if not enough time has passed since the potential exposure, it is possible to obtain false negative results, necessitating further testing.

For HIV testing: What is better – a spot test or an ELISA test?

A Spot Test for HIV detects HIV antibodies. The rapid test detects antibodies to HIV 1&2

An ELISA test for HIV also detects HIV antibodies.

Some ELISA tests for HIV detect antigen and antibodies (HIV DUO / 4th generation tests)

No HIV test can detect HIV immediately after infection.

Is HIV Spot Test a preventive test?

NO. It does not prevent HIV infection. It tests if you have HIV infection or not.

The window period for HIV p24 antigen is 28 days but can I test for it within 10 days?

A combination or fourth-generation test looks for both HIV antibodies and antigens.

Antigens are foreign substances that cause your immune system to activate. The antigen is part of the virus itself and is present during acute HIV infection (the phase of infection right after people are infected but before they develop antibodies to HIV).

Antigen can be detected between 14-21 days after infection.

So the answer to your question is NO. You cannot use the p24 antigen ELISA test to test for HIV within 10 days.

You are not testing virus at Disha Pathology, you are testing for antibody. How many days after infection will the antibody be detected?

At Disha Pathology we offer two types of HIV tests.

  1. HIV Spot test (Rapid Test)
  2. HIV p24 antigen and HIV 1&2 antibody test (ELISA Test)

So yes, we test for virus (antigen) and antibody in the same ELISA test

The time between when a person gets HIV and when a test can accurately detect it is called the window period. The window period varies from person to person and also depends upon the type of HIV test.

Most, but not all people, will make enough antigens and antibodies for fourth-generation or combination tests to accurately detect infection 2 to 6 weeks (14 to 42 days) after infection.

Antigens are foreign substances that cause your immune system to activate. The antigen is part of the virus itself and is present during acute HIV infection (the phase of infection right after people are infected but before they develop antibodies to HIV).

Antigen can be detected between 14-21 days after infection.

Antibodies are produced by your immune system when you’re exposed to viruses like HIV or bacteria. HIV antibody tests look for these antibodies to HIV in your blood.

The soonest an antibody test will detect infection is 3 weeks. Most (approximately 97%), but not all, people will develop detectable antibodies within 3 to 12 weeks (21 to 84 days) of infection.

What is the HIV PCR test?

PCR tests (polymerase chain reaction tests) – also test for the actual virus. This type of test is often used for testing the viral load of HIV-positive people, as well as testing babies born to HIV-positive mothers.

It looks for HIV in the blood. It looks for the virus and not the antibodies to the virus. This test is very expensive and not routinely used for screening individuals unless they recently had a high-risk exposure or a possible exposure with early symptoms of HIV infection.

Most, but not all people, will have enough HIV in their blood for a PCR / nucleic acid test to detect infection 1 to 4 weeks (7 to 28 days) after infection.

How often should you test yourself for HIV?

If you get an HIV test within 3 months after a potential HIV exposure and the result is negative, get tested again in 3 more months to be sure.

If you learned you were HIV-negative the last time you were tested, you can only be sure you’re still negative if you haven’t had a potential HIV exposure since your last test. If you’re sexually active, continue to take actions to prevent HIV, like using condoms the right way every time you have sex and taking medicines to prevent HIV if you’re at high risk.