The developed analytical standards were used to calculate the intra and inter-assay reproducibility of quantification for each virus-specific primer set. Mean C(t) values, standard deviation (SD) and coefficient of variation (CV) were calculated from the data obtained in three replicates of each standard dilution for the intraassay reproducibility, and in three real-time PCR assays consisted of three replicates each (nine total) for the inter-assay reproducibility. CV was calculated as SD/Mean C (t) * 100%.