Prevalence of Transfusion Transmitted Malaria Among Blood Donors and Evaluation of CarestartTM and Quantitative Buffy Coat Methodologies at Kenyatta National Hospital, Kenya

Abstract

Malaria is a disease of high economic importance that can be transmitted through blood transfusion in medical facilities Blood and its products are not screened for TTM in transfusion setups in sub Saharan Africa. The objectives of this study were to determine the prevalence of malaria parasite among voluntary blood donors, the performance characteristics and the level of agreement of two malaria screening techniques. The study applied cross sectional descriptive study design. The study involved recruitment of 155 voluntary blood donors. The blood samples were subjected to three malaria screening techniques which included microscopy, quantitative buffy coat and rapid diagnostic test. The study revealed that the prevalence of malaria infection among voluntary donors by microscopy was 3.2%, Quantitative buffy coat was 3.9 % and rapid diagnostic test was 5.2 %. The sensitivities of microscopy, rapid diagnostic test and quantitative buffy coat were 100%, 80 % and 100 %while the specificities of the three techniques were 100%, 97% and 99% respectively. The positive predictive values for microscopy, rapid diagnostic test and quantitative buffy coat were 100%, 97% and 83% and the negative predictive values were 100%, 99% and 100%. The kappa value for RDT was 0.63 and the kappa value for QBC was 0.90. The study revealed that Quantitative Buffy coat technique results compared favourably with microscopy because it picked almost all positives picked by the gold standard while Rapid Diagnostic Test yielded higher prevalence values above the other techniques because it picked more false positive values. The study revealed that quantitative buffy coat technique had higher sensitivity and specificity in detection of TTM than rapid diagnostic test. The study also established that there was substantial agreement between the gold standard and the RDT technique (0.63) and an almost perfect agreement between the gold standard and the QBC technique (0.90) therefore QBC was a viable screening technique for malaria parasites.