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Avoiding false positives: rapid HIV tests vary in their accuracy, so need to be used in combination

Posted on May 02, 2017

Source: aidsmap

Avoiding false positives: rapid HIV tests vary in their accuracy, so need to be used in combination

"An evaluation of eight rapid diagnostic tests widely used in a variety of African countries by Médecins Sans Frontières (MSF) shows that the tests vary in their performance, with false positive results being a concern. Samples from some geographical locations were more likely to have false positive results than others, suggesting that tests need to be locally validated, researchers report in the Journal of the International AIDS Society.

False negative results were rare.

The findings confirm that the diagnosis of HIV should not be based on results from a single HIV rapid diagnostic test. A combination of HIV tests, and more specifically an algorithm (sequence) of two or three different HIV rapid tests, is required to make an HIV-positive diagnosis. This is already recommended by the World Health Organization (WHO).

Misdiagnosing someone as having HIV can cause psychological trauma and profound social effects. Marriages may break down and people may take HIV treatment which they do not need.

Rapid diagnostic tests (RDTs) are the main diagnostic tool for HIV screening and diagnosis in resource-constrained settings. Despite their widespread use, there has been no systematic, head-to-head evaluation of their accuracy with specimens from diverse settings across sub-Saharan Africa. Experience from the field has suggested that, in some settings, some RDTs have sensitivities and specificities that are inferior to those recorded in WHO evaluations."

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