Neelam Bharihoke 1 , Praveen Singh 2 , Vaibhavi Subhedar 3 , Piyush Vyas 4
ABSTRACT: INTRODUCTION: Malaria continues to be a global public health challenge with more than 200 million deaths annually, specially in the tropical and subtropical countries.(1) In India malaria is endemic throughout the country, problem accounting for 1-2 million cases and 1100 deaths per year.(1) The commonly employed method for diagnosis of malaria involves the microscopic examination of Romanowsky stained blood films.(2) For decades light microscopy of blood smears has been the gold standard in the diagnosis of malaria.(3) It is labor intensive and requires considerable expertise for its interpretation, particularly at low level of parasitaemia.(4) The diagnostic modalities which are available for malaria range from conventional thick and thin smears, Quantitative buffy coat smears(QBC), to rapid and more reliable diagnostic modalities like antigen detection tests for detecting parasitic antigen like Histidine – rich protein-2 (HRP-2), Plasmodium lactate dehydrogenase (pLDH) and pan specific aldolase. These techniques have variable sensitivity and specificity.(5) Each of these methods have their own advantages and disadvantages. A previous study from India(6) had developed standardized and reported on using Centrifuged buffy coat smear (CBCS) examination for diagnosis of malaria, in which wide bore 4 ml tube instead of a Wintrobe’s tube has been used to obtain a buffy coat. This technique has advantage over the existing method. The purpose of the present study was to assess the usefulness of CBCS technique in comparison to peripheral blood smear and antigen detection. AIMS: Detection of malarial parasite by Centrifuged buffy coat smear (CBCS) was compared with conventional thin and thick peripheral smear and antigen detection by commercially available card test. The purpose of this study was to evaluate the usefulness of CBCS in comparison to peripheral blood smear and antigen detection. METHODS, MATERIALS AND RESULTS: A total of 837 patients were tested for malaria by all the three techniques. The maximum number of cases were positive by antigen test (230, 37.9%), followed by CBCS (214, 35.3%) and Peripheral smear (171, 28.2%). However, antigen test could not detect 04 cases, out of which one was picked up by both PS and CBCS and 3 by CBCS only. Antigen test was exclusively positive in 17 cases. A definite relationship was found with degree of parasitaemia. At high parasite level of >1000/microl, all the three tests detected malaria equally, but at lower level of parasitaemia (<200 parasites/microl) PBS could not detect in comparison with CBCS and antigen test in 28 and 25 cases respectively. Similarly at moderate parasitaemia (200-1000 parasites/microl) PS failed to detect 6 and 5 cases in comparison with CBCS and antigen test. The results of CBCS and antigen test correlated well. Thus by adding centrifugation to conventional PS, we could detect 43 more cases which included 26 with low level of parasitaemia. CONCLUSION: Though malaria antigen detection is considered gold standard for diagnosis of malaria, CBCS method has an advantage over peripheral blond smear in a country like India where antigen test and QBC are costly options.
