Human Immunodeficiency Virus (HIV) Test

What To Think About

• A rapid test (HIV-1/2 Ag/Ab Combo test) that can detect both HIV antibodies and HIV antigens is available. This test can detect an HIV infection earlier than other tests available. It also can tell whether an HIV infection is new or is established.
• After initial testing, it is important for your doctor to contact you with the results of your test. Be sure to tell your doctor how and where to contact you. If your doctor has not contacted you within 1 to 2 weeks of your test, call and ask for your results.
• The ELISA is a good screening test, because it is usually positive when an HIV infection is present. But the ELISA test results can indicate HIV is present when it is not (false-positive). So the ELISA alone cannot be used to make a definite diagnosis of HIV infection. No one is considered HIV-positive until he or she has a positive Western blot, IFA, or PCR test.
• Detecting HIV in a newborninfant is difficult. Until about 18 months of age, even a baby who is not infected may still have HIV antibodies received from his or her HIV-positive mother. A PCR test may be done to see if HIV genetic material (RNA or DNA) is present in the baby.
• To be certain that an HIV infection is not present, a person must test negative for the virus at least 6 months after the last possible exposure to HIV. Testing is often done at 6 weeks, 3 months, and 6 months to find out whether a person is infected.
• Two types of home test kits for HIV have been approved by the U.S. Food and Drug Administration (FDA). If the results from a home test kit show that you have an HIV infection, talk to a doctor. And keep in mind that these test kits sometimes may show that you have HIV when you don't (false-positive result) or may show that you don't have HIV when you do (false-negative result).
  • One test kit (called OraQuick) gives you the results right away. For this test, you rub your gums with a swab supplied by the kit. Then you place the swab into a vial of liquid. The test strip on the swab indicates if you have HIV or not.
  • Another type of test kit for HIV is a home blood test kit. This kit provides instructions and materials for collecting a small blood sample by sticking your finger with a lancet. The blood is placed onto a special card that is then sent to a lab for analysis. You can find out your results over the phone by using an anonymous code number. Counseling is also available over the phone for people who use the test kit.
• If you have a positive test result, contact your sex partners to inform them. They may want to be tested. You may be able to get help from your local health department to do this.
• A screening test for HIV infection may also be done on urine or saliva. An oral HIV test finds antibodies to HIV. Urine testing is rarely done.
• Oral test kits that find HIV-1 and HIV-2 in saliva have been approved by the United States Food and Drug Administration (FDA). The test results are provided the same day. Test results that show an HIV infection need to be confirmed by a Western blot test.
• Most states require health professionals, clinics, and hospitals to report confirmed cases of HIV infection to the state health department. Some states allow anonymous reporting (the person's name or other identifying information is not provided). Other states require confidential reporting (identifying information is provided but only to authorized public health officials). All states must report the numbers of cases of AIDS, without names or other identifying information, to the Centers for Disease Control and Prevention (CDC).
• After an HIV infection is present, other tests are done to determine when to treat the infection and how treatment is working. These tests include a CD4+ count and the viral load.
  • CD4+ Count
  • Viral Load Measurement
• Two types of HIV have been identified.
  • HIV-1 causes almost all of the cases of AIDS worldwide.
  • HIV-2 is found mostly in West Africa.