Kenya, Uganda VCTs turning in thousands of false HIV-positives

While the tests were found to be able to establish HIV-negative persons with a fairly high degree of correctness, some results were worrying.

In Kangemi, Nairobi, for example, the Uni-Gold test was found to have an accuracy of 99.13, meaning that out of every 10,000 HIV-positive people tested, 87 would wrongly be declared HIV-negative.

Say the researchers involved in the study: “With VCT uptake at government sites (rising), use of a single test could misdiagnose thousands of HIV-infected individuals. No rapid test is performed well-enough to recommend its use as a single diagnostic measurement.”

The researchers were led by respected Kenyan Aids scientist Prof Omu Anzala and included specialists from Uganda’s Virus Research Institute, Kampala’s Joint Clinical Research Centre, the Kenya Aids Vaccine Initiative (Kavi) and the International Aids Vaccine Initiative (IAVI).

According to NASCOP’s Dr Cherutich, about 2 to 2.5 million Kenyans visit VCT sites every year. Kenya’s Ministry of Health, he said, has instituted guidelines that at least all service providers use two rapid tests before informing their clients of their status.

Kenya has an estimated 1,000 independent VCT sites, which in total screen about 800,000 people annually. A similar number is tested at government hospitals voluntarily, and another 700,000 after seeking treatment, making up the total.

While acknowledging that “a significant” number of false positives are probably being reported with the rapid tests at various sites, Dr Cherutich was last week however categorical that the use of the methods was the most advisable for a country like Kenya.

“The rapid tests are cheap, easy to use and do not require special conditions such as refrigeration,” Dr Cherutich told The EastAfrican. “In our environment, where HIV/Aids is a national emergency, we should ask ourselves what is the most cost-effective screening method that can be rolled out nationally most effectively and efficiently.”

Because of their relative unreliability, however, rapid tests are no longer used in the Western world.

According to Dr Cherutich, the fact that the rapid tests are more likely to give false positives that declare an uninfected person HIV-positive is not an insurmountable obstacle.

“A false positive will probably be eliminated with subsequent tests,” Dr Cherutich said. “The rapid tests have given the fight against Aids a boost that we wouldn’t have otherwise had. We simply can’t afford PCR for everybody.”

Prof Anzala and his colleagues agree, but with an important rider — that the rapid tests be always administered with a confirmatory standard before a definitive HIV status is declared.

According to Kenya’s National Aids Control Council, there are an estimated 1.3 million Kenyans who are HIV-positive. Across East Africa, about five million people are thought to carry the Aids virus. Many would have been so declared at VCT sites.