The Science of HIV Tests

HIV tests showing positive resultsRegular HIV testing lets you keep an eye on your HIV status. But how does an HIV test actually work? With blood or oral fluid being used to detect the presence of the HIV virus in the human body, there’s clearly a method that doesn’t rely on blood itself to be accurate. So how does this work?

Your Body and Infection

One of the body’s defenses against illness—either via bacteria or viruses—is the immune system. This includes white blood cells that attack the invading bodies (antigens.) Engulfing and breaking down the antigen, the white blood cell (macrophage) spurs B cells into creating antibodies. These antibodies are coded to the antigen that was originally encountered by the white blood cell.

When the same antigen is encountered later, your body has the antibodies to immediately disable it. This is why you receive immunizations; the dead virus in a vaccine spurs your body to produce antibodies coded to that virus. If you encounter the antigen later on in your life, your immune system has the tools to handle the infection.

HIV Testing

How do HIV tests locate the antigen (the HIV virus) in your system?

The most common HIV test is the antibody screening test; this looks specifically for the antibodies that your body produces when it’s been exposed to HIV. If you’ve contracted the virus, your body’s immune system is already attempting to disable it. The production of these antibodies is a marker in your blood that the HIV test recognizes.

With this rapid testing—HIV testing can be accomplished in 30 minutes or less—it’s easy for people to have HIV testing done at least once a year or after any possible exposure. Due to the nature of the immune system and how long it takes antibodies to develop, it’s recommended that a negative HIV reading be followed up with an additional test.