A comparison of microscopic examination and rapid diagnostic tests used in Guyana to diagnose malaria

The aim of this study was to compare rapid diagnostic tests (RDTs) for malaria with routine microscopy for a prompt and accurate diagnosis of malaria and to provide an effective disease management in Guyana. Blood samples were collected randomly from 624 patients with clinical suspicion of malaria from four private hospitals in Georgetown, Guyana. The five different test methods [Paramax-3, Optimal-IT, VISITECT Malaria Combo PAN/Pf, Standard Diagnostic (SD) Bioline and conventional Giemsa stain microscopy] were performed independently by well trained and competent laboratory staff to assess the presence of malaria parasites. Results from the rapid diagnostic kits were analyzed and compared to those obtained by general microscopy. Of the 624 patients involved in the study, 197 (31.6%) tested positive and 427 (68.4%) tested negative to RDT whereas 190 (30.4%) tested positive and 434 (69.6%) tested negative to microscopy. The positive agreement index between RDT and microscopy was 89%. A comparison of microscopy with the RDTs, Paramax, Opitmal- IT, Omega, SD, showed a positive agreement index of 93%, 86%, 80% and 86%, respectively. The study, therefore, highlights the importance of both methods in diagnosis of malaria in endemic areas. Microscopy is the more reliable method in rural areas where malaria is most prevalent. RDT offers a good alternative, being an easy and rapid method that does not require an experienced laboratory technician.