Lab Tests

When you are tested for HIV, you probably will get the enzyme immunoassay (EIA), the standard test used. This test uses blood from a vein to detect the presence of antibodies to HIV. A positive result must be confirmed with another blood test such as the Western blot. More recent tests may use other body fluids, like oral fluid (not saliva) collected from the mouth or a urine sample, to identify antibodies.

Home testing kits: You collect a sample of blood using a finger stick or saliva, send it to a testing facility and find out the results over the phone several days later. You are offered a chance to speak to a counselor. These tests must be confirmed by the Western blot blood test.

Rapid tests: While EIA reports take up to several days to receive, a rapid test is a screening that gives results in less than an hour. This result must be confirmed with a follow-up test before a diagnosis can be made.

Viral load testing: This is a test that measures the relative amount of HIV in your body. Viral load tests measure the part of HIV that knows how to make more virus copies. These tests tell your doctor if you are at risk of getting sick and how effectively your medications are working.

Resistance testing: It is now possible to predict the effect of antiviral agents against HIV virus (susceptibility or resistance test). There are two commonly used tests - the genotypic test and the phenotypic test. These tests are able to predict if the HIV virus is developing resistance to the medications you are taking so that your doctor can tailor treatment depending on the results.

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This article was reviewed and updated June 2007.