HIV and AIDS

Testing for HIV

How do I get tested for HIV? What is an HIV test?

A simple blood test called the HIV antibody test can tell you if you have HIV.

There are in fact several different tests that can be administered to determine whether you have HIV. The first test developed—and still the most frequently used test for the initial detection of HIV infection—is the enzyme-linked immunosorbent assay, also known as ELISA or EIA. This test is usually performed by drawing blood from a vein in the arm. You should know that if you have blood drawn for an HIV test, it can take between one and two weeks before you know the results.¹

A negative result means that no antibodies to HIV were found in your blood at the time of testing. Testing is then complete.

If the ELISA test is positive, the testing laboratory will want to ensure the result is not a "false positive" by first repeating the ELISA test. If the result of the second ELISA is positive, you will likely need to undergo a second test, known as a Western blot.

If both the ELISA and the Western blot show a positive result, diagnosis of HIV infection is confirmed. This means you have been exposed to HIV and that you could potentially pass it on to others. It does not, however, mean that you have AIDS or that you will get it.

Most positive tests will show up within three months of a person's becoming infected with HIV. This is because the body needs time to produce antibodies after HIV infection has begun. For the vast majority of those who test positive, HIV antibodies develop within 4 to 6 weeks after exposure, although it may take a little longer in some people. To ensure you receive a reliable test result, it's important to wait at least 3 months or 13 weeks after your last possible exposure to HIV before being tested. Getting tested before 3 months can result in an unclear result or a false negative. Your doctor or testing facility may advise you to get tested again at six months. It's extremely rare for it to take longer than six months to develop detectable antibodies to HIV as the result of infection.²

While no diagnostic test is ever 100 percent reliable, if you test negative at the appropriate time (13 weeks after possible exposure to the HIV virus), you can be quite confident your test result confirms that you are HIV negative.

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1. Am I Infected? (A Complete Guide to Testing for HIV). AIDSMeds.com. (2004)
2. Am I Infected? (A Complete Guide to Testing for HIV). AIDSMeds.com (2004)