Figure 2

Linear regression analysis for determination of the theoretical gametocyte detection limit in 24 h-old DBS samples. QT-NASBA-1/TTP plotted against the log of gametocyte concentration per μl for each 24 h DBS filter paper sample duplicate. Dots represent the raw data and circles represent the average over a particular density. All storage conditions were summarised, as TTP-levels did not differ significantly. Linear regression analysis was performed based on all data points. The longest TTP was set to 90 minutes, indicated by the dashed vertical line. The mean theoretical limit of detection at 90 minutes (0.0095) was calculated and is indicated by the horizontal dashed line. The 95% confidence interval of the regression analysis was calculated with Scheffé’s method (0.0025 to 0.0380) per μl.