Indian Journal of Health Sciences and Care

Laboratory diagnosis of malaria still is a challenge for many laboratories in developing countries. There is an urgency on the part of clinician to obtain results accurately and quickly for initiating appropriate antimalarial therapy. The examination of Giemsa stained peripheral blood smear by light microscopy is an accepted and conventional method used for diagnosis of malaria. Most of the antigen detection-based assays use immunochromatographic procedures to capture the antigens. These assays are gaining popularity because they are simple, rapid and reliable.

A total of 1661 patients were enrolled for the study with suspected malaria. Patients were enrolled till 100 consecutive peripheral blood smears (PBS) were positive for malarial parasite. Out of remaining peripheral blood smears which were negative for malarial parasite (MP), by light microscopy a random selection of 200 samples was done as negative controls. These 300 samples (100 positive for MP by PBS examination and 200 negatives for MP) were subjected to rapid Diagnostic test (RDT) for malaria antigens HRP-2 and pLDH.

Of these 300 samples 101 were positive by RDT. Of these 101 RDT positive; 12 were diagnosed as Plasmodium falciparum, and 89 as Plasmodium vivax depending on presence of LDH and/or HRP2 antigen bands. Out of 101 RDT positive, 3 were negative by PBS and 2 samples were positive by PBS but negative by RDT.

This study concludes that RDT assay for diagnosis of malaria in comparison to PBS examination is reliable having sensitivity of 98.0% and specificity 98.5% RDT-antigen detection method for diagnosis of malaria being a simple assay is more suitable for use in the field and peripheral laboratories.