Quantitative Buffy Coat Malaria Test, QBC F.A.S.T.™ Test And SD Bioline™ Malaria Rapid Test in Malaria Diagnosis at Ahero Sub-County Hospital, Kisumu County

Abstract

Malaria is one of the leading causes of morbidity and mortality in Sub Saharan Africa. Effective management of malaria requires rapid and accurate diagnosis and prompt treatment with efficacious anti-malarial drugs. Accurate diagnosis of malaria requires laboratory confirmation of the presence of malaria parasites in the blood of a febrile patient. Conventional Giemsa stained peripheral blood smear examination remains the gold standard for diagnosis of malaria in developing endemic countries. However, this technique is time-consuming and difficult to interpret for inexperienced microscopists. Due to this, there is need for redoubled effort in the development of highly sensitive and robust point of care malaria diagnostics. The aim of this study was to evaluate the performances of Quantitative Buffy Coat (QBC), QBC Fluorescence and Staining Technologies™ [(QBC F.A.S.T.™) - improved QBC system] and SD BiolineTM malaria rapid test in malaria diagnosis from children< 5 yrs (n= 385) at ahero sub-county hospital, Kisumu county. Thick and thin blood smears in two replicates each were prepared then stained independently with Giemsa and F.A.S.T. Malaria stains for viewing of any malaria parasite present. Quantitative Buffy Coat capillary tubes were prepared for malaria parasite examination and SD Bioline rapid test done on the blood samples. Real-Time PCR was conducted on 40 % (n= 52) of 131 samples that were found to be positive by QBC and not by Giemsa. The Sensitivity of QBC was 90% (95% CI: 85-94), QBC F.A.S.T.TM 77% (95% CI: 71-83) and SD Bioline TM 91% (95% CI: 86-94). The Specificities were 30% (95% CI: 24-37), 83% (95% CI: 77-88) and 67% (95% CI: 60-73) P < 0.01 respectively. Positive Predictive Value (PPV) for the tests were 58% (95% CI: 52-63), 83% (95% CI: 77-88) and 74% (95% CI: 63-80) whilst Negative Predictive Values (NPV) were 74% (95% CI: 63-84), 78% (95% CI: 71-83) and 87% (95% CI: 81-92) respectively. Although the standard QBC malaria test and the SD Bioline™ malaria RDT showed better sensitivity relative to the improved QBC F.A.S.T. ™ test, the latter had a better specificity. The performance of these tests remains modest against microscopy. Quantitative Buffy Coat F.A.S.T. TM test can be used as a point-of-care malaria device although further studies should be done to test the efficacy of the test in malaria diagnoses especially quantitative diagnoses on low parasitaemia and a distinct visual morphology of the Plasmodium malariae.