Insights into the Performance of SD Bioline Malaria Ag P.f/Pan Rapid Diagnostic Test and Histidine-Rich Protein 2 Gene Variation in Madagascar.

histidine-rich protein 2 (PfHRP2) forms the basis of many current malaria rapid diagnostic tests (RDTs). However, the parasites lacking part or all of the gene do not express the PfHRP2 protein and are, therefore, not identifiable by PfHRP2-detecting RDTs. We evaluated the performance of the SD Bioline Malaria Ag P.f/Pan RDT together with variation in Madagascar. Genomic DNA isolated from 260 patient blood samples were polymerase chain reaction (PCR)-amplified for the parasite 18S rRNA and genes. Post-PCR ligation detection reaction-fluorescent microsphere assay (LDR-FMA) was performed for the identification of parasite species. histidine-rich protein 2 amplicons were sequenced. Polymerase chain reaction diagnosis of patient samples showed that 29% (75/260) were infected and was present in 95% (71/75) of these PCR-positive samples. Comparing RDT and detection by LDR-FMA, eight samples were RDT negative but positive (false negatives), all of which were positive. The sensitivity and specificity of the RDT were 87% and 90%, respectively. Seventy-three samples were amplified for , from which nine randomly selected amplicons were sequenced, yielding 13 sequences. Amplification of , combined with RDT analysis and detection by LDR-FMA, showed that there was no indication of deletion. Sequence analysis of showed that the correlation between sequence structure and RDT detection rates was unclear. Although the observed absence of deletion from the samples screened here is encouraging, continued monitoring of the efficacy of the SD Bioline Malaria Ag P.f/Pan RDT for malaria diagnosis in Madagascar is warranted.