The underperforming Abbott-Bioline Malaria Ag P.f/P.v rapid diagnostic test: a whiter shade of pale - where the truth is not plain to see

Abstract

The Abbott-Bioline™ malaria antigen Plasmodium falciparum and Plasmodium vivax rapid diagnostic test (Abbott-Bioline™ Malaria Ag P.f/P.v RDT) is used widely in the Greater Mekong Subregion. It is approved by the World Health Organization (WHO) and deployed on a large scale in the regional malaria elimination programmes. Following reports of false-negative test results from field-workers, the Abbott-Bioline™ Malaria Ag P.f/P.v RDT was compared with microscopy in 187 persons with fever during a vivax malaria outbreak in Myanmar. Among them 11 tested positive for P. vivax using the Abbott RDT, while 46 were diagnosed with P. vivax malaria by microscopy. The sensitivity of the Abbott RDTs among febrile patients was 0.24 (95% CI 0.12-0.36) with a specificity of 1.0. Twenty-eight (61%) of the 46 patients had a parasite count of ≥200/µL, the WHO-recommended lower limit of detection for RDTs. Among these 11 were detected by the Abbott malaria RDT, a sensitivity at this threshold of 0.39, (95% CI 0.21-0.57). The colour band denoting positivity on the malaria RDT was often absent. The low intensity of the RDT colour band was confirmed objectively using ImageJ®, an image processing software. The Abbott-Bioline™ Malaria Ag P.f/P.v RDT is insensitive compared to microscopy. In remote areas where there is very limited access to health care and usually only a single source of diagnosis and treatment, as in rural Myanmar, this has resulted in dangerous delays in patients receiving appropriate treatment. The WHO Incidents and Substandard/Falsified Medical Products Team was informed of the problem, but did not respond effectively. Deployment of the underperforming malaria RDT continues.