Evaluation of a rapid and inexpensive dipstick assay for the diagnosis of Plasmodium falciparum malaria

Rapid, accurate and affordable methods are needed for the diagnosis of mala ria. Reported here is an evaluation of a new immunochromatographic strip, t he PATH Falciparum Malaria IC Strip, which is impregnated with an immobiliz ed IgM monoclonal antibody that binds to the HRP-II antigen of Plasmodium f alciparum. In contrast to other commercially available kits marketed for th e rapid diagnosis of falciparum malaria, this kit should be affordable in t he malaria-endemic world. Using microscopy and polymerase chain reaction (P CR)-based methods as reference standards, we compared two versions of the P ATH test for the detection of P. falciparum infection in 200 febrile travel lers. As determined by PCR and microscopy, 148 travellers had malaria, 50 o f whom (33.8%) were infected with P. falciparum. Compared with PCR, the two versions of the PATH test had initial sensitivities of 90% and 88% and spe cificities of 97% and 96%, respectively, for the detection of falciparum ma laria. When discrepant samples were retested blindly with a modified proced ure (increased sample volume and longer washing step) the sensitivity and s pecificity of both kits improved to 96% and 99%, respectively. The two rema ining false negatives occurred in samples with <100 parasites per mu l of b lood. The accuracy, simplicity and predicted low cost may make this test a useful diagnostic tool in malaria-endemic areas.