A comparative study of blood smear, QBC and antigen based rapid diagnostic test for diagnosis of malaria

Abstract

Background and Objectives: Rapid diagnosis is prerequisite for effective treatment and reducing mortality and morbidity of malaria. Microscopy has been the Gold standard for malaria diagnosis for decades. We made an attempt to compare blood smear, Quantitative Buffy Coat (QBC) and rapid antigen detection methods for the rapid diagnosis of malaria. Methods and Materials: A retrospective study was conducted for 6 months in G.G. Hospital, Jamnagar. A total number of 90 hospitalized clinically suspected malarial cases were collected and confirmed by conventional blood smear, QBC and antigen based Rapid Diagnostic Test (RDT). Blood smears were prepared and stained with Leishman stain. QBC and Rapid Diagnostic tests were done using commercially available kits. Patients were followed-up for signs of clinical recovery. Results: Malaria was diagnosed in 50, 54 and 59 patients by Leishman staining technique, QBC method and Rapid antigen detection test respectively. Sensitivity, specificity, positive and negative predictive values of Antigen detection test were 94%, 70% 79% and 90%, respectively while, those of QBC were 84%, 77%, 82% and 79%, respectively. The sensitivity of rapid diagnostic test is high with grade 3 and 4 parasitemia. Conclusion: In our study, rapid diagnostic tests were found more accurate than PBS and QBC. Microscopy is cost effective but microscopy and QBC requires technical expertise to interpret the results. In places where facilities are not available, rapid, simple and easy to interpret antigen detection test can be used, especially in endemic areas.