Evaluation of Rapid Methods in Malaria Diagnosis from Persons attending Primary Health Facilities, Ogun State, Nigeria

Abstract

Malaria in Nigeria is treated blindly in most cases and where diagnostic measures exist, efficacies of several are still in doubt. This study evaluated performance of microscopy and rapid (RDT) methods in confirming  prevalence of malaria parasites (MP),parasite species and percent  parasitized red blood cells in 384 persons systematically selected from seven primary healthcare facilities in Ogun State, Nigeria from October to December 2012. Giemsa thin and thick film techniques and RDT (SD Bioline Ag P.f/Pan kit) were employed on the blood samples. Data were analysed using SPSS version 16. Demographic results showed that females were 61% and males 39%,but of varying age groups. Seventy-one percent of the blood samples were positive for MP by microscopic blood films,
and only 24% samples were positive by RDT. Paired sample T-test showed a significant difference (P=0.000)between microscopy and RDT methods. Of the 273 positive blood samples,95.6%were P. falciparum,3.3% were P. malariae, 0.7% was P. ovale and P. vivax (0.4%). For RDT, P. falciparum was 74% while mixed infections were 26%. Prevalence in risk groups 0–10 and 11–20 age groups was observed to be higher with significant  differences (p=0.011, p=0.023) for both microscopy and RDT respectively. RDT sensitivity and specificity were 23.4% and 74.7% compared to microscopy. Positive Predictive Value and Negative Predictive Value were 69.6% and 28.4%. The efficiency of the RDT was 38.3%. The low sensitivity of RDT observed means that malaria diagnosis by microscopy method remains the gold standard.

Keywords: Rapid Diagnostic, microscopy, malaria parasites, health facilities, Ogun State.