By: David Menino, Health Educator,
Harbor Health Services, Inc.
Rapid HIV antibody tests have increasingly become commonplace in both clinical and nonclinical settings, and can improve access to testing and reduce unrecognized infections. According to the 2011 Health of Boston report prepared by the Boston Public Health Commission, Boston’s HIV incidence rate from 1999-2009 has decreased by 57%. However, neighborhoods such as Dorchester still have a slightly higher incidence rate—35.5 new cases per 100,000 (North Dorchester = 39.6 per 100,000; South Dorchester = 31.5 per 100,000.)—than the Boston city-wide average of 27.4 cases per 100,000. Many places, like Geiger Gibson Community Health Center on Tuesdays from 3pm – 7pm and Neponset Health Center on Wednesday from 3pm – 7pm, provide free and anonymous walk-in HIV tests that allow patients to receive their result during the visit. Rapid testing can allow people to be more cognizant of their behavior and how it relates to HIV.
In general there are two types of rapid HIV antibody tests that are used: an oral swab (Oraquick), or one that requires a small amount of blood (Clearview) via finger stick (analogous to the amount used for blood sugar testing). Both tests work by testing for HIV antibodies, not the actual virus itself. When a person is infected with HIV, their immune system produces antibodies to try and fight against the virus. These antibodies are found in the blood and oral mucosal transudate, which is a fluid in the cheeks and gums (the oral swab is not using saliva!). The reason why antibodies are used is because they are disease-specific: the immune system produces antibodies in response to the presence of proteins for a specific disease—which are called antigens, and they bind together in a lock and key fashion. After collecting the oral fluid or blood sample, a developing enzyme is used. This enzyme reacts to the binding of the HIV antibody and HIV antigen. Therefore, as the sample and enzyme make its way up the testing strip, they encounter the HIV antigen substance. If HIV antibodies are present, they bind to the antigen and the enzyme reacts, causing a color change on the strip. The rapid tests allow for a quick, reliable screen for HIV infection, and can improve routine screening behavior and promote HIV awareness for neighborhoods like Dorchester.