Systematic assessment of commercially available low-input miRNA library preparation kits

We compared the performance of six commercial kits (QIAseq, SMARTer, CATS, CleanTag, srLp, TailorMix) capable of handling <100ng total RNA input for miRNA detection sensitivity, reliability, titration response and ability to detect differentially expressed miRNAs at different amounts of synthetic miRNAs. We observed differences in detection sensitivity between the kits, but none were able to detect the full repertoire of expected miRNAs. The reliability within the replicates of all kits was good, while larger differences were observed between the kits, although none could accurately quantify the majority of miRNAs. Systematic comparison of miRNA profiles assessed in low-input synthetic miRNA samples and samples from pools of blood derived CD8 T cells of rheumatoid arthritis (RA) patients or healthy controls (HC) by six commercially available library preparation kits. Altogether five different miRNA mixes were created (denoted mix A to mix E). Mix A and Mix B consisted of the equimolar miRNA pool supplemented with the non-equimolar pool present at eight different concentration ratios between the two mixes spanning a 100 fold range. Mix C was a titration of 0.75 mix A and 0.25 mix B, while mix D was a titration of 0.25 mix A and 0.75 mix B. In the case of mixes A-D, the total miRNA concentration was 30 nM, with individual equimolar miRNAs present at 30 pM and other miRNAs ranging from 3-300 pM. Mix E consisted of the same miRNAs as mix A but at a 10-fold lower concentration.