The sensitivity and specificity of a urine based Rapid Diagnostic Test for the diagnosis of plasmodium falciparum in a malaria endemic area in Odisha, India

Abstract

Background: Rapid and accurate diagnosis is crucial in the treatment of malaria. Rapid Diagnostic Tests (RDTs) using blood have been recommended by the WHO as an acceptable method for the diagnosis of malaria. RDTs provide results quickly, is simple to use and easy to interpret. However, its use requires collection of blood by skin puncture. Hence the aim of the pilot study is to explore the sensitivity and specificity of RDTs using urine (collected non-invasively) for diagnosis of Plasmodium falciparum malaria and to assess the relation between parasite density in blood with HRP-2 Ag detection in urine. Material and Method: All fever cases admitted to Ispat General Hospital (IGH) Rourkela, India, during June 2012-March 2013 with a clinical diagnosis of malaria were examined for the presence of asexual forms of P. falciparum in peripheral blood smears. All smear positive febrile patients who met the eligibility criteria were enrolled. Smear negative fever cases were enrolled as control cases. RDTs were performed using both urine and blood samples by using commercially available blood specific kits. Results: Sixty blood smear positive cases and 51 febrile blood smear negative cases were enrolled. Sensitivity and specificity of RDT urine were 86.67% (95%CI:75.83–93.09) and 94.12% (95%CI:84.08–97.98) respectively whereas those of RDT blood were 91.67% (95% CI: 81.93–96.39) and 98.04% (95% CI 89.7–99.65). The sensitivity of both RDT urine as well as RDT blood were found to be dependent on the level of parasitemia. Conclusion: Results of this study are promising. Larger studies are needed to assess whether RDTs using urine could serve as a practical, reliable method for the detection of P. falciparum in a non-invasive manner where invasive blood taking is less feasible.

Keywords:

• Malaria
• diagnosis
• Rapid Diagnostic Test
• urine
• blood

Acknowledgement

The authors wish to dedicate this article to the memory of Late Dr. Saroj Kanti Mishra. Dr. Mishra was pioneer clinician and scientist in the field of malaria and an inspiration for his colleagues. His contribution to tropical medicine and in the management of severe malaria saved many lives.