COMPARATIVE EVALUATION OF THE DIAGNOSTIC ACCURACIES OF THREE RAPID MALARIA TESTING KITS

Ifeanyi T. Nzekwe*, Chukwuma O. Agubata, Samuel C. Umeigbo, Chigozie E. Utazi, Charles O. Esimone, Ifeanyi E. Okoye

ABSTRACT

The rapid testing kits used in malaria detection in Nigeria are deemed by some health professionals to have the same diagnostic efficiency as microscopy and some have advocated their use in non-invasive testing. This study aims at evaluating the comparative diagnostic efficiencies of three commercially available kits in relation to microscopy, using invasive and non-invasive methods. Matched blood and saliva from 50 symptomatic patients were tested for malaria using three rapid tests, with microscopy as gold standard. Data were analyzed using Cochran’s Q and McNemar’s tests. Out of the three brands tested, only one was in agreement with microscopy when blood was used as specimen, with the other two differing at 5% confidence interval. Saliva-based testing demonstrated high specificity, while blood-based testing demonstrated higher sensitivity and accuracy and there was no correlation with blood-based testing for all the three brands (p < 0.05). There were no statistical differences between the outcomes of saliva-based testing for the three tests (p > 0.05). Two-third of the RDTs tested were significantly inferior to thick smear microscopy, with blood used as test specimen. Also, testing with saliva gave significantly lower sensitivity than blood-based testing for each RDT. Rapid testing kits should not be solely used as confirmatory test for malaria and saliva should not be substituted for blood.

Keywords: Sensitivity, malaria, detection, rapid, infectious disease.