Comparative evaluation of malaria antigen test and peripheral blood smears in diagnosis of malaria

Introduction: Malaria is a serious, sometimes fatal, parasitic disease posing a major public health problem in India. Microscopic detection of blood though considered the gold standard for malaria diagnosis for decades is quite labor-intensive and requires adequate technical skill and manpower. This has spurred the development of malaria rapid detection tests (RDT) based on the detection of malarial antigen in whole blood.

Aim: In this study, malaria antigen test was compared with peripheral blood smears from PUO cases in Tuticorin, Tamilnadu from January 2016 to June 2018. A total of 5603 samples were collected from patients presenting with fever, chills, and rigor throughout 2 1/2 years. Thick and thin blood smears were prepared, stained with Leishman stain and examined. SD BIOLINE Malaria antigen detection kit test used for detection of malaria.

Results: Malaria was diagnosed in 422 and 442 patients by malaria antigen test and Leishman staining respectively. The prevalence rate of malaria by card test was 7.5% (422 out of 5603), of these 343 (6.1%) Plasmodium vivax positive and 79 (1.4%) Plasmodium falciparum. Peripheral smears for malarial parasite 442 (7.9%) and 363 (6.5%) positive for Plasmodium vivax and 79 (1.4%) Plasmodium falciparum. The blood smear examination could detect 20 positive cases of Plasmodium vivax which were not detected by card test.

Conclusion: Our evaluation shows that malaria antigen card test is a simple, reliable and rapid test for the diagnosis as well for speciation of the malarial parasite. The test can be a promising alternative to microscopy in remote and rural areas of our country and as a supplement to microscopy in tertiary care centers.

Keywords: Malaria, Peripheral blood film, Rapid test.