Rapid Malaria Antigen Test
Four species of Plasmodium are responsible for the majority of human malaria cases, including Plasmodium falciparum (P. falciparum), P. vivax, P. malariae and P. ovale. A fifth species, P. knowlesi, has been recognized as causing disease similar to P. falciparum infection in Southeast Asia, particularly Malaysia.
Rapid identification of malaria infections and differentiation of P. falciparum from other malarial parasites is a time-critical diagnosis. Traditional diagnosis depends upon microscopic identification of malarial organisms in peripheral blood. Although microscopy is sensitive, the timing of specimen collection is vital for optimal results. Microscopy requires technologist experience and expertise.
Recently, an immunochromatographic assay became available for testing of blood specimens for malaria antigen. The test detects histidine-rich protein II (HRPII) antigen, which is specific to P. falciparum, as well as a pan-malarial antigen common to all four major species. The clinical limit of detection for P. falciparum is 1000-1500 parasites/uL. The test distinguishes between P. falciparum and non-falciparum species. Because lower levels of parasitemia may not be detected, follow-up testing of negative results is recommended when suspicion for infection is high. Follow-up testing may include malarial smears, additional malaria antigen testing or malaria PCR. The test may not detect P. knowlesi.
Specimen requirement is one EDTA tube of blood.
