Amplification efficiency determination via LRE analysis. As described in detail in an earlier study , LRE analysis produces a linear representation of PCR amplification in which amplification efficiency (EC) is linearly coupled to amplicon quantity (FC). Best exemplified by cycles within the central region of an amplification profile, this linear relationship allows the application of linear regression analysis to a 4–6 cycle window (designated by red circles) from which amplification efficiency is determined from the Y-intercept, defined as the maximal amplification efficiency (Emax, equation 3). As amplicon DNA reaches detectable quantities, amplification rate decreases substantively as defined by the slope (ΔE, equation 3), with the reaction fluorescence reaching a maximum (Fmax, X-intercept) as amplification rate approaches zero. The low variances produced by LRE analysis, as summarized in the tabular inlay, reflects the high level of similarity in profile shape produced by each of the five target quantities.