RT-qPCR and RT-ddPCR parallel analysis of PMMoV RNA serial dilutions. (A) Correlation between the log serial dilutions and determined concentrations (log target/10 μl reaction mixture) for the RT-qPCR and RT-ddPCR. For each method, the linear regression is plotted, with the equation for the correlation coefficient (R2) given. (B) Coefficients of variation for the measurement of each of the serial dilutions within the linear range. The dotted horizontal line indicates the maximal acceptable coefficient of variation for the determination of the limit of quantification.