How reliable were malaria self-tests sold online?

Details

Malaria rapid diagnostic tests (RDTs) for travelers to use for self-diagnosis were previously considered suboptimal because of poor performance. Self-diagnosis RDTs are now marketed and available online. This study assessed the diagnostic accuracy and the quality of labeling, contents and instructions for use (IFUs) of products marketed for self-diagnosis.

Researchers assessed eight RDT products using a panel of stored whole-blood samples: 90 samples comprising the four Plasmodium species and 10 Plasmodium-negative samples. They assessed IFUs for their descriptions of the procedure and interpretation, layout and readability, and recorded packaging and content errors.

Two products produced false-positive test lines in 70% and 80% of the Plasmodium-negative samples, precluding their use. Of the six remaining products, four had good to excellent sensitivity for diagnosing Plasmodium falciparum (98.2%–100.0%) and Plasmodium vivax (93.3%–100.0%). Sensitivity for Plasmodium ovale and Plasmodium malariae was poor (6.7%–80.0%). All but one product produced false-positive test lines when read beyond the recommended reading time.

Three products did not specify their target antigens on the label, and six contained desiccant without a humidity indicator. IFUs had major shortcomings in descriptions of the test procedure and interpretation, poor readability and layout, and user-unfriendly typography. None addressed strategic issues such as the need for repeat testing and reasons for false-negative results.

Diagnostic accuracy varied: only four of eight products were reliable for diagnosing P. falciparum and P. vivax, and none was reliable for P. ovale and P. malariae. The researchers concluded that IFUs, including their content and user-friendliness, as well as labeling and product contents, need improvement before the tests can be considered for travelers’ self-diagnosis.