Comparison of the ParaSight™-F test and the ICT Malaria Pf™ test with the polymerase chain reaction for the diagnosis of Plasmodium falciparum malaria in travellers

Abstract

Rapid and accurate methods are needed for the diagnosis of imported malaria. The ParaSight^™-F test and the ICT Malaria Pf^™ test are commercially available kits marketed for the diagnosis of Plasmodium falciparum malaria. Both tests are antigen-capture assays based on the detection of P. falciparum histidinerich protein 2 in peripheral blood. Using microscopy and a polymerase chain reaction (PCR)-based method as reference standards, we performed a ‘blinded’ comparison of these assays for the detection of P. falciparum infection in 200 febrile travellers returning from malaria-endemic areas. As determined by PCR and microscopy, 148 travellers had malaria and, of these patients, 54·7% (81/148) were infected with P. vivax only, 31·1% (46/148) with P. falciparum only, 9·5% (14/148) with P. ovale, 0·7% (1/148) with P.malariae, and 4·1% (6/148) had mixed infections. Compared to PCR, the ParaSight^™-F and ICT Malaria Pf^™ tests had initial sensitivities of 94% and 90% and specificities of 95% and 97%, respectively, for the detection of P. falciparum malaria. When discrepant samples were retested with day 0 and day 1 bloods, the sensitivities improved to 96% and 94%, respectively. The 2 remaining false negative results with the Para-Sight^™-F test and 2 of the 3 false negative results with the ICT Malaria Pf^™ test occurred in samples with P = 0.75) and both are simple, rapid, and accurate tests for the detection of P. falciparum infection in the returned traveller.