What is an HIV test?
The HIV test is designed to determine whether you have been infected with HIV--the virus that causes AIDS.
When you get infected with HIV, your body sees the virus as an invader and begins to produce cells and particles to fight it. These particles are called antibodies. The HIV antibodies are different from antibodies for the flu, a cold, or other infections. If you have HIV antibodies, then you have been infected with HIV.
The HIV test detects antibodies to HIV. It requires a small sample of blood from a vein or a finger-stick, although some newer tests use fluid from your mouth. Because it can take the body several months to make antibodies, your test results might be negative if you get tested too soon after becoming infected. Most infected persons test positive within 2-8 weeks after infection, and almost all (97%) will test positive at 3 months after infection. A very few won't test positive until 6 months after infection.
The HIV test does not tell you if you have AIDS, how long you have been infected, or how sick you might be.