Researchers found that inaccurate HIV status test results were not due to the tests being damaged by improperly storing them above the recommended temperatures. It must be operator error, they concluded.
Storing HIV testing kits improperly is unlikely to cause the erroneous readings often reported in low-income areas, a study in Malawi shows.
Rapid diagnostic tests (RDTs) can be housed at higher-than-specified temperatures and reviewed months later without affecting results, researchers found.
Augustine T. Choko, an assistant research epidemiologist, along with colleagues at the Malawi Liverpool Wellcome Trust in Blantyre, Malawi, published their findings in PLOS on June 22, 2016. They were joined by contributors from Liverpool and London in the UK.
The team evaluated oral fluid test OraQuick Advance HIV I/II (OraSure Technologies Inc.) and whole blood tests Determine HIV 1/2 (Alere Inc.) and Uni-Gold Recombigen HIV (Trinity Biotech). Two of each manufacturer’s tests were administered to adults at a Malawi health center. One of each RDT pair had been exposed to prolonged 37°C (98.6°F) temperatures, while the other had been stored at the optimal 18°C (64.4°F). The study found that pre-incubating RDTs at the higher temperature for 28 days did not substantially affect the diagnostic accuracy.
The researchers also evaluated the stability of used OraQuick kits by delaying the re-reading of test results. In all but two cases, both involving patients taking antiretroviral therapy, initial visual reads were stable over a one-year follow up period, the team reported.
The study did not look at the effect of humidity on the tests and did not exclude patients taking ART drugs.
“Our results, showing robustness of the kits to poor storage and late read, are consistent with current understanding that identifies poor operator practice as the major determinant of misclassification,” the researchers reported.
Inaccuracies in HIV testing can result in detrimental consequences, the researchers wrote. A person falsely diagnosed as HIV-positive may face unnecessary worry and be inappropriately placed on antiretroviral therapy. A person who is erroneously found to be HIV-negative may miss out on care and prevention services.
“The need to build systematic proficiency testing into routine HIV testing programs has become strikingly apparent with reports of poor operator practice and high rates of misclassification in many African national programs,” the researchers said.
As HIV screenings continue and patient self-testing expands, countries may be able to rely on visual re-reading of RDTs as they revise their approaches to quality assurance, the researchers noted.