Low specificity of a malaria rapid diagnostic test during an integrated community case management trial.

Abstract

IntroductionParasitological confirmation before administration of antimalarial treatment has been recommended by the World Health Organization in everyone presenting with symptoms suggestive of malaria at all levels of the health system.MethodsThe authors assessed the performance of a histidine-rich protein 2-based malaria rapid diagnostic test used by community health workers in the context of an integrated approach to diagnosis and treatment for malaria and pneumonia. A total of 525 children below 5 years of age were recruited into the study. Children with fever/history of fever within the last 24 h were tested with the rapid diagnostic test (RDT) and a blood smear was obtained for delayed reading.ResultsOverall, the FirstSign™ Malaria Pf (Unimed International Inc, South San Francisco, USA) has shown a high sensitivity profile of 97.9% (95% CI 96.3–98.8), but a low specificity of 53.4% (95% CI 49.1–57.7). The specificity was significantly lower during the high transmission season at 25.4% (95% CI 20.5–31.0) compared to 63.7% (95% CI 57.6–69.4%) at the low transmission season. The negative predictive value (NPV) was 95.4% (95% CI 93.2–96.9) and positive predictive value was 71.7% (95% CI 67.7–75.4). The NPV was significantly higher during the low transmission season at 98.2% (95% CI 95.7–99.3) than compared to 80.0% (95% CI 74.7–84.4) at the high transmission season.ConclusionWith such a low specificity, caution should be exercised when using these RDTs for community case management of malaria.