Interpreteation of immunochromatographic tests with HRP-2 antigen in children under 5 years in an area of high risk of malaria transmission in Papua New Guinea

The immunochromatographic tests with HRP-2 antigen (histidine-rich protein) Vision Biotech Pf Rapid Malaria Test was performed in 291 children under 5 years presenting fever or history of fever (malaria presumptive cases) admitted to Children Out-Patient Department of the Modilon Hospital in Madang, in a high malaria risk area of Papua New Guinea. The results of the tests were compared to the results of the parasitic examination of the peripheral blood with light microscopy (thick and thin smears). The HRP-2 test showed very high sensitivity (95.4%) and specificity (94.1%) for Plasmodiumfalciparum parasitaemia and none or very low sensitivity and specificity for other malaria species. The HRP-2 test detected both asexual and sexual stages of the Plasmodium falciparum parasites. The test did not show significant changes in detection of different levels of parasitaemia. These findings enable to conclude that the HRP-2 immunochromatographic assay can be very helpful to diagnose Plasmodium falciparum malaria when microscopy examination is not available, but as qualitative tests can be difficult for interpretation especially in high malaria risk areas. Therefore it can require re-examination of blood with microscopy to confirm species and development stages of Plasmodium spp. and to assess parasite load.