What we can do about HIV

In this section you’ll read about testing for HIV, anti-HIV drugs, drug resistance, and HIV vaccines.

Testing for HIV

The standard blood test for HIV, called an ELISA test, doesn’t actually detect the virus itself. Instead, it detects antibodies to the virus. If antibodies are found in a person’s blood, the person is HIV-positive. If no antibodies are found, the person is HIV-negative.

It can take three to 14 weeks before your immune system responds to HIV by producing antibodies. This delay is called the window period and it makes testing for HIV more difficult.

If a person is infected with HIV but the test is taken before antibodies develop, the test result may be misleading. The test may indicate the person is HIV-negative even though the person is infected with HIV.

If you think you might have been exposed to HIV you should wait 14 weeks before you get tested because it may take that long before your body starts producing antibodies.

The ELISA test is very good, but it’s not perfect. Occasionally the test will give a false-positive result. In other words, a blood sample tests positive even though there is no HIV in the sample. To be absolutely sure, in Canada all positive tests are double-checked using a different kind of test called a Western blot.