Performance of Field Evaluated Malaria Rapid Diagnostic Tests

The introduction of malaria rapid diagnostic tests (RDTs) has enhanced quick examination of blood samples from suspected malaria patients; however, it is not clear which RDT is the most appropriate in different endemic areas with mono and mixed infections of different parasites.

Regardless of the setting, RDTs require minimal operator training, and yield highly reproducible test interpretations. RDT results are normally rapidly available when the physician is actively managing patients as the test can be completed in less than 20 minutes. They do not require any instrumentation, electricity, special laboratories, or water and these kits are generally cost-beneficial.

Scientists at the Kenya Medical Research Institute (Nairobi, Kenya) and their colleagues evaluated commercial RDTs for malaria on 500 study participants. The study participants included 290 (58%) children younger than 12 years and the other 210 ranged in age from 13 to 64 year. The 181 male participants were a minority of participants while the majority of the participants were the 319 females. The 196 adult women who were not pregnant comprised 39% of the female population.

The team assessed the performance of BinaxNow, SD Bioline, CareStart Malaria, and First Response. These RDTs were compared to thin and thick blood film microscopy and real time polymerase chain reaction (PCR). Amplification and real-time measurements was performed in the AB 7500 analytical PCR system from Applied Biosystems.

Of the 500 participants recruited, 33% were malaria positive by microscopy while 51.2 % were positive by PCR. Compared to microscopy, the sensitivity of the RDTs to detect malaria parasites was 90.3% to 94.8 %, the specificity was 73.3% to 79.3%, the positive predictive value was 62.2% to 68.8%, and the negative predictive value was 94.3% to 96.8%. Compared to PCR, the sensitivity of the RDTs to detect malaria parasites was 71.1% to 75.4%, the specificity was 80.3% to 84.4 %. The RDTs had a moderate measure of agreement with both microscopy of more than 80.1 % and PCR of more than 77.6 %.

The authors concluded that rapid diagnostic tests can be applied in a number of settings with a great potential for impact on public health where they can significantly improve the quality of malaria case management in areas where expert microscopy or PCR methods are not available. This study demonstrated that CareStart, SD Bioline, BinaxNow, and First Response RDTs performed reasonably well in this endemic region for the detection of Plasmodium falciparum. The study was published on September 7, 2016, in the Malaria Journal.

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Kenya Medical Research Institute