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HIV Testing
HIV antibody testing has been available since 1985. It is believed that many people who are HIV infected in the United States have not been tested, and are unaware of their HIV-positive status. Many of these people may not realize that they are infected with HIV until they present with symptoms of infection. Also, it is important for people to realize that a negative HIV test is not a safeguard if they engage in behaviors that put them at risk for HIV.
There are several approved tests that are available to detect HIV antibodies. These tests determine HIV infection by detecting the presence of HIV antibodies produced by the immune system.
The Food and Drug Administration (FDA) has approved several HIV antibody tests. Currently, they include blood, urine, rapid, oral mucosal transudate and home HIV antibody tests. At this time, these all utilize the ELISA test method.
The ELISA (EIA) Test
The first screening test done on a blood sample is called the enzyme linked immunosorbent assay (ELISA, also called EIA). This test screens for the presence of antibodies to HIV. There is a small chance that the ELISA may also detect proteins related to other autoimmune diseases. The CDC recommends against telling a person s/he is HIV-positive based only on ELISA test results.
HIV Western Blot Assay
If a person has two reactive (positive) ELISA tests on the same blood sample, a confirmatory test, such as the Western Blot test is done to confirm the presence of HIV antibodies. The HIV Western Blot detects antibodies to individual proteins that make up HIV. This test is much more specific and more costly than the ELISA screening test.
Urine HIV Test
A urine-based test for HIV antibodies is available for use only in the out-patient offices of healthcare providers or medical clinics at this time. It tests for HIV antibodies in the urine. It is important to note that, even though antibodies to HIV can be found in urine; urine is not considered a risk for transmitting the virus.
A positive urine HIV screening test must be confirmed with a Western Blot test, which can be done on the same specimen.
Oral Fluid HIV Test
This test detects HIV antibodies in the mucous membrane of the mouth, called oral mucosal transudate. It is important to note that, even though antibodies to HIV can be found in saliva and oral fluids, these are not considered a risk for transmitting the virus. The test kit uses a special collection device that looks like a toothbrush. No needles are necessary.
Recently, a new (2005) oral fluid HIV test has been developed and is gaining popularity due to its ease of use, accuracy and quick results. The findings can often be determined in less than 20 minutes. Only one such test is currently FDA approved (OraQuick Advance by OraSure Technologies).
This new development begs the question as to whether it is appropriate for these tests to be administered in a dental office setting. This question was discussed in the September, 2005 issue of JADA. Administering an oral fluid HIV test would be a good service for patients. However, there are many things to consider when providing such a service. Specialized training would be required in order to understand the full spectrum of the undertaking. Oftentimes, counseling is necessary following an HIV test regardless of what the outcome is. Someone in the dental office should be available to sit down with the patient and explain what his or her test results mean. This can often prove a complicated task for an under trained dental employee. However, if a dental care provider would take the time to acquire the necessary skills, the oral HIV test would be a great service to patients in the dental office.
Any person testing positive with this test must have a Western blot test to confirm the results. The confirmatory test can be done on the same specimen.
Rapid HIV Test
Guidelines for rapid HIV testing were changed in October, 2005 (see http://www.doh.wa.gov/cfh/HIV_AIDS/Prev_Edu/rap_test_05.htm) for specific details. The HIV rapid testing can be done using oral fluid specimens or through fingerstick using whole blood. Any positive rapid test must be confirmed with a conventional Western Blot test.
The rapid test has been recommended for use on source patients in healthcare worker occupational exposures, so that the healthcare worker can make an informed decision regarding post-exposure treatment. The test is expensive and at this time is not generally available at public testing sites.
Home HIV Test Kits
Currently, the only licensed and FDA-approved test kit for home HIV antibody testing is manufactured by Home Access®. The test kit is sold in pharmacies, or may be ordered through a toll free number from Home Access®. The test requires a few drops of blood, which is mailed to the company in a safe mailer.
A confirmatory Western Blot test can be done on the same sample. The person calls the company to learn their results over the phone.
Internet Test Kits
Although other "home test" kits may be ordered over the internet, they may not be approved by the FDA. They are not guaranteed to be accurate. It is not recommended to use any test, which has not been approved by the FDA.
Other Tests for HIV
The p24 antigen test is a blood test measures a core protein of HIV. This protein occurs during primary infection (the first few weeks of infection) but may disappear as soon as antibodies to the virus are present. Because of this, and because of the expense of the test, p24 antigen tests are currently only available in specific circumstances.
The HIV RNA or proviral DNA test are blood tests may be run for people with suspected new HIV infection. They are expensive and not used as screening tests for the general public. However, anyone who has had a potential exposure to HIV through unprotected sex or sharing needles, and who presents with symptoms of primary infection (usually seen within the first two weeks of infection with HIV) should ask their medical practitioner if this test is advisable. Primary infection is discussed later in this course.
HIV viral load test measures the amount of HIV in an infected person's bloodstream. It is rarely used to diagnose HIV infection. It is most often used in individuals who are HIV-positive to measure the effectiveness of antiretroviral medications used to treat HIV infection.
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Tested for HIV
