Since the beginning of the HIV epidemic, more than 70 million people have been infected with the HIV virus and about 35 million people have died of HIV. Globally, about 36.7million people were living with HIV at the end of 2015. Sub-Saharan Africa remains most severely affected, with nearly 1 in every 25 adults (4.4%) living with HIV and accounting for nearly 70% of the people living with HIV. In Uganda, the prevalence of HIV infection is about 7.1% generally.
HIV testing facilities diagnosis of HIV infection after a client has received counseling services
Test results may come out true or false. A True test result may be a true positive or a true negative while a false test result may be a false negative or a false positive
A false negative result is failure to correctly identify an HIV-infected person as HIV-positive.
A false positive result is an incorrect HIV-positive diagnosis in a person who is not actually infected.
True positive and true negative results are correct identifications of the presence and absence of HIV, respectively.
The ideal HIV screening test would correctly identify all HIV-positive and HIV-negative individuals 100% of the time but the available methods do not achieve 100% accuracy.
False negative results are most likely to occur during the window period that is when antibodies (substances produced by the body to neutralize the virus) and antigen (body parts of the virus) are not yet present at detectable levels in the sample to be tested. This takes from 3 weeks to several months and very rarely up to a year! After exposure to the virus
Conversely, false positive results may occur if non-HIV antibodies are incorrectly identified as antibodies to HIV. This could be due to other current viral infections in the individual being tested other than HIV
Other causes of false results may be due to poor sample collection or processing, use of expired or wrong test kits. This contribute a very small percentage of wrong results
Because of the risk that a positive result from a single test is, in fact, a false positive, many doctors prefer to talk about the result being ‘reactive’ rather than ‘positive’. The result will need to be replicated in confirmatory testing before an HIV-positive diagnosis can be made.
In Uganda, a total of up to 3 tests are used if the first blood test is positive. If one isn’t satisfied with the result, then tests can be repeated in a different health facility