Diagnostic methods of malaria in Eastern Nepal: a comparative study of traditional and two rapid diagnostic tests

Abstract

This study compared the diagnostic accuracy of Quantitative Buffy Coat (QBC) a fluorescent microscopy test and OptiMAL, an immunochromatographic dip stick test against conventional microscopy for the detection of malaria at a tertiary teaching hospital situated in Eastern Nepal. 100 clinically suspected malaria patients with positive and negative parasitemia were assessed under conventional microscopy. The blood samples withdrawn from these subjects were further evaluated by the QBC Method and OptiMAL dipstick test. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of QBC and OptiMAL tests as compared with microscopy were 100%, 100%, 100%, 100%, 1 and 96%, 100%, 100%, 96.15% and 0.98 respectively. In Nepal, thick and thin blood smears remain the gold standard for malaria species diagnosis in routine diagnostic laboratories. In this study the efficacy of newer malaria rapid diagnostic tests (RDT) surpassed the diagnostic efficacy of clinical microscopy and hence these RDT's will have a greater role in clinical practice. The cost of QBC technique may impose limitations on its use in Nepal but the OptiMAL test is likely to play an important part in urgent malaria diagnosis.