A Comparative study of Peripheral blood smear examination, Quantitative Buffy Coat method and immunochromatography test in the diagnosis of malaria

Abstract

Abstract : Several diagnostic methods are in use for the    diagnosis of malaria. The present study was carried out to study the efficacy of thin peripheral blood smear examination (PBS) quantitative buffy coat (QBC) examination,                              immunochromatography test (ICT) and to identify the species of malarial parasite. The study population consisted of 75 patients with fever and chills. Thick PBS,thin PBS, QBC and ICT were positive in 56,48,52 and 52 of patients respectively. The results were statistically analysed with SPSS version-20 software and P value determined using Chi square test. Considering thick peripheral blood smear examination as the gold standard, the sensitivity and specificity of thin blood smear was 78.5 and 90.9,that of QBC 85.7 and 90.9 and ICT 92.8 and 100 respectively. The false positivity of thin PBS, QBC and ICT were 9.1, 9.1 and 0 respectively. These tests had a false negativity of 21.4, 14.2 and 7.1 respectively. Thin PBS, QBC and ICT  detected 75, 33 and 77 of P.vivax, 16, 7 and 0 of P.falciparum and 8, 0 and 23 mixed infection respectively.Conclusion The frequency of detection of malaria was more by thick PBS     examination. Thin PBS showed more false negativity than other tests. Though QBC had a high sensitivity, species identification was not possible in all cases. ICT had 100 specificity with no false positivity. The rate of detection of mixed infection was more by ICT than thin PBS.ICT can be used as an adjunct to the thick PBS examination for diagnosis of malaria.

Keyword :Peripheral smear, Quantitative buffy coat,   immunochromatography test