HIV
Human immunodeficiency virus (HIV) testing determines whether or not you're infected with HIV, a virus that weakens your immune system and can lead to acquired immunodeficiency syndrome (AIDS). Some HIV tests check for antibodies that your immune system produces in reaction to HIV infection. Other HIV tests look for evidence of the virus itself. Rapid tests can produce results in less than 30 minutes.
No special preparations are necessary for HIV testing. You may need to call your doctor to schedule an appointment. Some public health clinics may allow you to simply walk in for HIV testing.
HIV is usually diagnosed by testing your blood or a sample of cells taken with a cotton swab from inside your cheek for the presence of antibodies to the virus. Urine samples can also be tested for HIV antibodies, but the results are slightly less accurate.