[Serum HRP-2 antigens and imported Plasmodium falciparum malaria: comparison of ParaSight-F and ICT malaria P.f]

Abstract

Serum levels of HRP-2 antigens against Plasmodium falciparum in 568 venous blood samples collected at two general hospitals were evaluated using the ParaSight-F (Becton-Dickinson) alone (568/568 samples) or in combination (156/568 samples) with the new ICT-Malaria P.f. (ICT-diagnostic). Comparison with the reference method (thin and thick blood smears assessed by two experienced parasitologists) showed that both tests were highly sensitive (93% and 96% respectively) and specific (98% and 98% respectively). The positive predictive values of the two tests were equal (96%) and the negative predicative values were close (96% and 98% respectively). Although both tests provided results within 10 minutes and required no special equipment for interpretation, the ICT-Malaria P.f. test seemed simpler and easier to use than the ParaSight-F test. The ParaSight-F test alone was used to monitor serum antigen levels after treatment in 24 patients. Antigen levels remained positive for at least three days after disappearance of circulating parasites (range: 3 to 28 days). Evaluation of serum levels of HRP-2 antigens can be useful for emergency diagnosis, especially in patients with low circulating parasite levels. The ICT-Malaria P.f. test seems especially suited for in-field use.