Experts agree that human immunodeficiency virus (HIV) testing is essential in stopping the spread of the disease. There are three main types of HIV tests: antibody tests, RNA tests, and a combination test. All tests are designed to detect HIV-1, which is overwhelmingly the most common type of HIV in the United States.
Antibody tests look for HIV antibodies in the body, rather than looking for HIV itself. Unfortunately, these HIV antibodies do not eliminate the virus, but their presence serves as a marker to show HIV infection.
The common screening test for HIV is a blood test known as the enzyme immunoassay (EIA) or enzyme-linked immunosorbent assay (ELISA). Antibody tests may also use oral fluid (not saliva) or urine to detect HIV antibodies. Oral fluid is collected by swabbing the gums or inside cheek area.
There are also home HIV antibody tests. Currently the Home Access HIV-1 Test System is the only home blood test approved by the U.S. Food and Drug Administration (FDA). This is a sample-collection kit, not a true HIV testing kit.
A drop of blood is added to a test strip and then mailed to a laboratory. At a later date, one calls the lab for results. The FDA also approved a kit that tests for antibodies in oral fluid called OraQuick.
The polymerase chain reaction (PCR) test detects specific deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) sequences that indicate the presence of HIV in the genetic structure of someone infected with HIV.
The HIV combination test detects antibodies directed against HIV-1 or HIV-2, as well as a protein called p24, which forms part of the core of the virus. It takes weeks for antibodies to form after the initial infection, even though the virus and the p24 protein is present in the blood. Thus, combination testing may allow for earlier HIV detection.
Rapid HIV testing uses blood, oral fluid (not saliva), or urine to detect HIV antibodies and allows results to be ready in 5-30 minutes.
The Centers for Disease Control and Prevention wrote that the OraQuick In-Home HIV Test can provide rapid results at home. This involves swabbing the mouth for an oral fluid sample and then testing it. Results are available in 20 minutes.
Although HIV tests are very sensitive, unfortunately they can produce false-positive results.
According to the University of California, San Francisco Medical Center it is important to supplement positive results with a confirmatory test, such as the Western blot or indirect immunofluorescence assay (IFA).
The IFA test detects antibodies made to fight an HIV infection. The Western blot test detects specific protein bands that are present in an HIV-infected individual. In combination with a positive ELISA, a positive Western blot is 99.9 percent accurate in detecting HIV infection.
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Reviewed February 20, 2014
by Michele Blacksberg RN
Edited by Jody Smith