Fig. 2

True positivity rates, determined from quantification of a serial dilution of DNA from blood-stage parasites, for Plasmodium berghei (a, orange) and Plasmodium chabaudi (b, blue). Mean Ct values ± SEM are presented for P. berghei (0.001–6428 genomes/PCR) and P. chabaudi (0.05–75,461 genomes/PCR), tested in n = 12 replicates unless stated otherwise on the graph. The LOD (concentration at which the true positivity rate drops below 1) ± SEM, predicted using a plateau-linear function is 4.4 (Ct 36.7 ± 0.5) or 0.8 (Ct 38.4 ± 0.1) genomes/PCR for P. berghei and P. chabaudi, respectively (dotted lines ± shading). Ct, Cycle threshold; LOD, limit of detection; Pb, Plasmodium berghei; Pc, Plasmodium chabaudi; SEM, standard error of the mean