About HIV : How is HIV Diagnosed?

The most common method of HIV antibody detection uses an enzyme linked immunosorbent assay (ELISA) test for screening, followed by confirmation with the Western Blot test. Accuracy of HIV serologic testing is very high (> 99% sensitivity and specificity). Reports of the results may take from two days to two weeks following submission of the sample, depending on the laboratory doing the work. Common testing locations include health departments, hospitals, private doctors, family planning or sexually transmitted disease clinics, mobile sites, drug treatment facilities, and sites specifically dedicated to HIV testing.

Some alternative tests are also available.

• Home Access Express Test is the only available home test for HIV. Filter paper with a blood sample obtained with a lancet is mailed to a laboratory in a coded, anonymous process. Dried blood samples are tested by the same ELISA and Western Blot tests used on venous blood. Sensitivity and specificity approach 100%. Results are provided by phone (a recorded message for those with negative results, counseling for those with positive results).
• Three rapid tests are available that provide results in about 10 minutes: SUDS, Recombigen, and Genie. Sensitivity approaches 100%; specificity is also 99%. These tests are also based on blood.
• The OraSure test uses ELISA and Western blot testing to detect antibodies to HIV in saliva. Sensitivity and specificity are similar to that with standard serology.
  

A great deal of controversy has surrounded the role of HIV testing. Most questions regarding testing and its value have centered on civil rights rather than medical issues. Earlier in the epidemic, the right to privacy and concerns about confidentiality of results, as well as fears of discrimination against people found to be infected have limited the use of the test for general screening.

However, the medical value of an early diagnosis has gained greater prominence in relationship to HIV infection. While the disease is still not curable, it is treatable through medical interventions. Appropriate treatment delays disease progression and prevents opportunistic infections. A positive serological diagnosis also allows an individual to plan priorities (as is true with any long-term, chronic illness) and - very importantly - it allows that person to avoid infecting others, including the partner they love.

Knowledge of infection gained through HIV testing is also important to mothers and infants. Through perinatal antiretroviral treatment we can reduce the risk transmission of the virus from an infected mother to her newborn by as much as 80%. This benefit was so dramatic that in June of 1996 the American Medical Association called for the mandatory HIV testing of all pregnant women.

Next: How Does the Disease Progress?