Figure 6.

Values of KOD and SOD related of each amplification curve versus Log of inhibitor concentration. Symbols (squares and dots) represent the χ² values related to each amplification curve obtained in the presence of different inhibitor concentrations. The horizontal continuous lines are the critical values for detecting outliers (left panels: the KOD χ² critical value is 3.84; right panels: the SOD χ² critical value is 7.81; with α = 0.05). Different inhibitors were used: Tannic acid (A-B), IgG (C-D) and Quercitin (E-F). True outliers (represented by black symbols; squares for KOD and dots for SOD) are amplification curves with Log(N_ob/N_exp) ratio out of 95% confidence interval, while white symbols represent acceptable runs with Log(N_ob/N_exp) ratio included in 95% confidence interval. The 95% confidence interval has been obtained from the amplification curves of the standard samples. The black symbols, over the horizontal continuous line, are runs correctly detected as outliers. Conversely, black symbols under this line are undetected outliers.