The effect of luminogenic substrate choice on the determination of IC
values. Trophozoite stage Dd2luc (2% parasitaemia, 2% HCT) were incubated for 48 hrs in the presence of the indicated concentration of drug prior to measurement of the absolute mean RLU ± stdev (n = 3) using (A) chloroquine and (C) artemether. Normalizing these data as a fraction of the controls (% growth) allows a dose–response curve to be plotted for each luminogenic substrate for (B) chloroquine and (D) artemether. The IC50 values determined for each luminogenic substrate (see key in Figure2) are shown.