A trial study on a mixture of Acridine and Giemsa stains and modified Quantitative Buffy Coat for detection of malaria parasites

Abstract

Microscopy after Geimsa staining remains the gold standard technique for detection of malaria parasites while Acridine is a common fluorescent stain that enhances the visibility of parasites. Combination of both stains could further enhance the performance of microscopy technique. The aim of this study was to investigate the efficacy of staining with mixture of Acridine and Giemsa and modified Quantitative Buffy Coat technique in detection of plasmodium parasites. Five hundred and seventy (570) volunteered students attending the Kwara State University Health Center Malete with history malaria fever and tested positive for malaria parasite were re-examined with the two methods being investigated. Two millilitres of the blood sample from each subject was collected into EDTA container and mixed properly. Thick smears were made in duplicate from each sample and properly labeled, stained by Giemsa and Acridine-Giemsa techniques and examined under x100 objective of the microscope while the remaining blood samples were also tested by Modified QBC. The study assessed the Sensitivity, Specificity, Positive Predictive Value and Negative Predictive Value of both techniques with respect to Giemsa microscopy as a gold standard. Findings from the investigation showed that modified QBC and Acredine-Giemsa techniques recorded sensitivity of 100% and 99.7% respectively. Concentrated Acridine-Giemsa stain recorded higher specificity (90.7%) than modified QBC with 82.5% using Geimsa staining as a gold standard. The Positive Predictive Value (PPV) for Modified QBC and Acredine-Giemsa techniques were 96.8% and 96.5% respectively whereas the Negative Predictive Value (NPV) for both methods were 100% and 98.7% respectively. In conclusion, the finding depicts a keen competition between Acridine-Giemsa staining method and Modified QBC technique for detection of malaria parasites and there was no significant difference in the efficacy of both methods with respect to detection of malaria parasite.

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Keywords: Acridine-Giemsa, Modified QBC, Efficacy, Microscopy, Gold standard