Comparisons among samples obtained in different blood collection tubes.

The library concentrations (A), identification rate (B) and UMI ratios (C) were evaluated and compared among samples obtained in EDTA-2Na, EDTA-2K, NaF and citrate blood collection tubes. The mean miRNA expression profiles observed following the use of EDTA-2Na vs. EDTA-2K (D), EDTA-2Na vs. NaF (E) and EDTA-2Na vs. citrate (F) were compared. MiRNAs with levels that exhibited a fold change greater than 2-fold or less than half-fold are indicated outside of the dashed lines. The x-axis or y-axis of the scatter plot indicates log2(miRNA expression counts). The Venn diagram indicates that 24 miRNAs exhibited expression levels that were aligned across all tubes, while the levels of 1 and 28 miRNAs were increased only in NaF or citrate tubes, respectively (G). The expression levels of hsa-miR-451a (H), an indicator of hemolysis, and hsa-miR-126-3p (I), an indicator of platelet contamination, are shown. The crossbar indicates the mean, and the error bar indicates the standard deviation (SD). Significant differences were identified using one-way ANOVA with a post hoc Tukey test and are indicated as * p<0.05, ** p<0.01 and *** p<0.001.