Sharbati et al. BMC Genomics 2012, 13:23 http://www.biomedcentral.com/1471-2164/13/23 Page 6 of 11 Figure 4 Reproducibility and accuracy of miR-Q arrays. Tukey box plots in Figure 4A show the inter-assay distribution of normalised values (ΔCq = Cq miRoI-Cq norm) of the 6 replicates. Each value was calculated as the mean of triplicate intra-assay measurements. Standard deviations (SD) of 6 replicates are given adjacent to the box plots. According to the MIQE guidelines we determined the accuracy of miR-Q arrays by spiking total RNA samples with 3.3, 33 and 330 pM synthetic miRNA (let-7e, miR-143 and miR-145). Fold differences between 3.3 and 33 pM (figure 4B) as well as 33 and 330 pM (figure 4C) were determined applying the ΔΔCq algorithm.