HIV-1 AntibodyAnticuerpo contra el VIH-1

HIV-1 Antibody

Does this test have other names?

HIV test; human immunodeficiency virus antibody test, type 1

What is this test?

The test looks for HIV-1 antibodies in your blood.


Because the findings are not considered definite unless you have two tests, your doctor will likely do two types of testing on your blood sample:

  • ELISA (enzyme-linked immunosorbent assay), a highly sensitive screening test for HIV

  • Western blot, a test widely used to confirm the results  

There is an HIV-2 virus, but HIV-1 is more common. When people say "HIV," they are usually referring to HIV-1.

Why do I need this test?

You may have this test if you have symptoms of an HIV-1 infection. Early symptoms are flu-like and include:

  • Fever

  • Cough

  • Sore throat

  • Runny or stuffy nose

  • Muscle aches

  • Headaches


You may have this test if you have shared needles to inject drugs. Needle-sharing has been linked with the spread of HIV infections.

You may also have this test if you are diagnosed with a different sexually transmitted disease (STD). This is because STDs generally suggest the possibility of high-risk behavior.

What other tests might I have along with this test?

Your doctor will also order a Western blot test if your ELISA test is positive. Your doctor may also order viral load testing if he or she suspects you have an acute HIV infection.

What do my test results mean?


Normal results for the ELISA test are negative, meaning you have no HIV-1 antibodies in your blood. If the ELISA test is positive for HIV-1 antibodies, your doctor will confirm this result with a Western blot analysis of your blood.

Normal results for the Western blot test are negative. The Western blot uses electrical fields to find antibodies, and the results appear as bands on a computer screen. If two out of three bands appear, the test is considered positive.

If both the ELISA and the Western blot test are positive, it means you likely have HIV-1.

Because the test looks only for the presence of HIV-1 antibodies, you might be infected with HIV but get a false-negative result. ELISA may not find antibodies for weeks or even months after your exposure to the virus. Your doctor may have you repeat the test weeks or even months later if he or she suspects your result is false-negative.

You may have a false-positive result if you have an autoimmune disorder, recently received a flu shot, or are taking part in an HIV vaccine trial.

Depending on your results, your doctor may suggest that you speak with an HIV counselor.

How is this test done?


Does this test pose any risks?


What might affect my test results?

Timing is important. Getting the ELISA test too soon after exposure to HIV-1 may give a false-negative result.

How do I get ready for this test?

You don't need to prepare for this test.


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