LABORATORY DIAGNOSIS OF MALARIA, A REVIEW

BACKGROUND: The gross number of malaria cases is on the increase worldwide mainly due to limitations of traditional methods for malaria diagnosis. Even though peripheral smear examination of thick and thin film is widely accepted for detecting Plasmodium, species identification and for parasite count; it has its own pitfalls. Sensitivity of quantitative buffy coat is 41-93%, specificity is >93% for P. falciparum whereas <52% for non-falciparum when parasitemia is 0.002%. With availability of optimal reagents Immunochromatographic tests are being manufactured with different combination of target antigens to suit local malaria epidemiology. OptiMAL has high sensitivity compared to microscopy and ICT but low when compared to PCR. Serological tests are more useful for screening blood donor in case of transfusion- induced malaria with low parasitemia not detectable by blood film. PCR is used for detecting drug resistant strains, genotyping of Plasmodium strains. Placental histology is the best method for diagnosing malaria in pregnancy.