Assessment of the capability of the platforms to recover known miRNA copy number differences. The ability of the platforms to recover known four-fold miRNA copy number differences between samples was assessed by calculating ΔCt's for 125 synthetic miRNAs common to both the TaqMan and miRCURY platforms. Shown are boxplots of the ΔCt's obtained for TaqMan (A, C) and miRCURY (B, D). Recovery was assessed both in the synthetic samples i.e. consisting solely of synthetic miRNAs (A, B) and the plasma RNA samples spiked with synthetic miRNAs (C, D). Separate plots were made for miRNAs that were four fold higher (ΔCt = 2) and lower (ΔCt = -2) in sample 1 compared to 2.