Figure 1

Comparison of quantitative real-time PCR standard curves. 10-fold plasmid or gDNA dilutions were plotted against Ct values generated from qPCR only and nested qPCR assays using (A) P. falciparum 18S rRNA plasmid or (B) gDNA extracted from dried blood spots obtained from a subject with clinical malaria as template DNA (described in the Methods). Points represent the mean of technical duplicates and error bars (where visible) indicate the standard deviation. Dotted lines represent the technical limit of detection as defined as the lowest template concentration for which there is a linear relationship between Ct values and copy number/parasite density. For (C), Ct values generated by nested qPCR were plotted against the parasite densities estimated from copy number for P. falciparum 18S rRNA plasmid or corresponding to the dilutions from the clinical DBS standards. The best-fit regression line is shown as a black line.