Evaluation of methods for the laboratory diagnosis of malaria in Guyana

ABSTRACT

When 297 blood samples taken from patients attending a fever clinic in Georgetowm Public Hospital were examined microscopically, after thick and thin blood films had been stained with Giemsa, one hundred and forty-two (47.8 percent) were microscopically positive for malaria. After processing the patients' serum samples by the Indirect Fluourescent Antibody (IFA) technique, specific IgG and IgM antibodies were detected in 239 (81.3 percent) and 179 (60.1 percent), respectively, of the sera. Based on the microscopical findings, the IFAT gave positive and negative values of 54.4 percent and 81.8 percent (IgG), and 57.5 percent and 67.8 percent (IgM), suggesting that the IgM would be more useful than the IgG in the diagnosis of current malaria. An odds ratio analysis showed that the presence of symptoms, IgG or IgM antibodies, as well as visits to endemic regions, could be good indicators of current malaria. Age and occupation are not. The microscopical method will continue to be the gold standard - the best available criterion for the validation of our tests - for our diagnosis of acute malaria. (AU)