Results:168 children with uncomplicated malaria(median (inter-quartile range) age 44 (39–47) months) were enrolled, 80.3% with Plasmodium falciparum monoinfection,14.9% with Plasmodium vivax monoinfection, and 4.8% with mixed P. falciparum/P. vivax infection.All responded to allocated therapy and none had a malaria-positive slide on Day3. Consistent with a median baseline WBC density of 7.3 (6.5-7.8) × 109/L, there was no significant difference inbaseline parasite density between the two methods regardless of Plasmodium species. BlandAltman plots showed that, for both species, the mean difference between pairedparasite densities calculated from assumed and measured WBC densities was closeto zero. At parasite densities <10,000/μL by measured WBC, almost all between-method differences werewithin the 95% limits of agreement. Above this range, there was increasing scatterbut no systematic bias.
Conclusions:Diagnostic thresholds and parasiteclearance assessment in most PNG children with uncomplicated malaria arerelatively robust, but accurate estimates of a higher parasitaemia, as aprognostic index, requires formal WBC measurement.