HIV-1 Antibody Test (ELISA and Western Blot)

What is the HIV-1 antibody test?

The HIV-1 antibody test checks your blood for antibodies to the most common type of the human immunodeficiency virus (HIV-1). HIV is the virus that causes AIDS (acquired immunodeficiency syndrome), a life-threatening disease. If you are infected with HIV, your immune system makes a type of protein called an antibody to try to destroy or get rid of the virus.

There are different HIV antibody tests. One test is the ELISA (enzyme-linked immunosorbent assay). If the ELISA test is positive, a second test called a Western blot is done to confirm the result. The Western blot takes longer to perform and is more expensive than the ELISA test, but it is more precise.

A new quick HIV test has been recently approved by the US FDA.

Why is this test done?

This test is done to see if you are infected with the virus that causes AIDS. This test is also used to screen donated blood for HIV.

How do I prepare for this test?

No special preparation is needed for this test.

How is the test done?

A small amount of blood is taken from your finger or your arm. Blood from a finger prick is put in a vial of solution and tested with at dipstick. Blood taken from your arm with a needle will be sent to a lab for testing.

Having this test will take just a few minutes of your time. There is no risk of getting AIDS, hepatitis, or any other blood-borne disease from this test.

How will I get the test result?

Ask your heath care provider when and how you will get the result of your test. Results from the quick HIV test may be available in 30 minutes or less. You may get results from other HIV tests in 2 to 10 days.

The test results should be confidential and should not be revealed to anyone without your permission.

What do the test results mean?

In general, a positive HIV test means that you are infected with HIV, and a negative test means that you are not infected with HIV. The test does not directly measure or identify the HIV virus in the blood, however. Instead it measures antibodies that the body makes in response to the viral infection. Because it takes at least a few weeks for the antibodies to appear in the blood after infection by the virus, it is possible to have a negative test if you have been recently infected (this is called a false-negative test). In this case, the test will become positive if it is repeated several weeks or months later. If you have a negative test result but you are in a high-risk group, you may need to have another test 3 to 6 months later.

Although the HIV tests are very precise, sometimes the test result can be positive even though you do not have HIV infection (this is called a false-positive test). For this reason, when a positive result occurs, labs automatically perform a second HIV test (Western blot) to check the result.

What if my test result is positive?

If your first test for HIV is positive, you should have more blood tests to confirm the results. If repeat tests are positive, you should seek medical care, even if you have no symptoms. In some cases you may need to start taking medicine to try to stop the HIV infection from developing into AIDS. You need to discuss the test results with your health care provider or an HIV counselor as soon as possible to protect your health and the health of people you love.