What are common sized libraries observed on a TapeStation, Bioanalyzer, or similar instruments?
When using single indexes, pure miRNA libraries are approximately 180 bp, and pure dimer libraries are approximately 157 bp. If there is a peak at approximately 165–173 bp, this comprises "RNA fragments or other small RNAs that aren't miRNAs"; these are common to see in total RNA samples, being particularly strong in biofluid total RNA samples. Even if a peak is observed at 175–173 bp, there is still likely miRNAs present in the sample. Any RNA that has a 3’ OH and 5’ PO4, and is approximately 50 bp and smaller, should be robustly captured by the QIAseq miRNA Library Kit.
When using the miRNA UDI indexes, pure miRNA libraries are approximately 200 bp, and pure dimer libraries are approximately 177 bp. If there is a peak at approximately 185–193 bp, this comprises "RNA fragments or other small RNAs that aren't miRNAs"; these are common to see in total RNA samples, being particularly strong in biofluid total RNA samples. Even if a peak is observed at 185–193 bp, there is still likely miRNAs present in the sample. Any RNA that has a 3’ OH and 5’ PO4, and is approximately 50 bp and smaller, should be robustly captured by the QIAseq miRNA Library Kit.
When using the miRNA UDI indexes, pure miRNA libraries are approximately 200 bp, and pure dimer libraries are approximately 177 bp. If there is a peak at approximately 185–193 bp, this comprises "RNA fragments or other small RNAs that aren't miRNAs"; these are common to see in total RNA samples, being particularly strong in biofluid total RNA samples. Even if a peak is observed at 185–193 bp, there is still likely miRNAs present in the sample. Any RNA that has a 3’ OH and 5’ PO4, and is approximately 50 bp and smaller, should be robustly captured by the QIAseq miRNA Library Kit.