The dynamics of amplification efficiency under a sigmoidal paradigm. (A) A Log(FC) vs. cycle number plot of the predicted sigmoidal FC dataset taken from the 1,880 molecule profile presented in Figure 4. This reveals a log-linear region that is nearly identical to that produced by the actual FC dataset (Figure 6). The numerical inlay summarizes the results of the linear regression analysis. Numbers above and below the plot are the respective FC and EC values predicted for each cycle. (B) Plotting -Log of the loss in cycle efficiency vs. cycle number produces a linear region, illustrating an exponential loss in amplification efficiency within the log-linear region. (C) Plotting the loss in amplification efficiency against reaction fluorescence expressed as a percentage of Fmax generates a line, reflective of the linear relationship between amplification efficiency and amplicon quantity. This provides a simple method for estimating the loss in amplification efficiency based on expressing reaction fluorescence as a percentage of Fmax. Close correlation between the predicted (red circles) and actual (dots) values is maintained down to the point at which read precision is compromised by low reaction fluorescence, as reflected by the two lowest actual EC values. The numerical inlay summarizes the results of the linear regression analysis based on the actual EC, excluding the two lowest values.