How can I check the integrity of RNA purified using RNeasy Kits?

The integrity and size distribution of total RNA purified with RNeasy Kits can be checked by denaturing-agarose gel electrophoresis, the Agilent 2100 bioanalyzer, or the QIAxcel Advanced System with the QIAxcel RNA QC Kit v2.0.

The respective ribosomal species should appear as sharp bands on the stained gel. 28S ribosomal RNA bands should be present with an intensity approximately twice that of the 18S RNA band. If the ribosomal bands are not sharp, but appear as a smear of smaller sized RNAs, it is likely that the RNA sample has suffered major degradation during preparation.

Size of ribosomal RNAs from various sources

Source	rRNA	Size (kb)
E. coli	16S	1.5
	23S	2.9
S. cerevisiae	18S	2.0
	26S	3.8
Mouse	18S	1.9
	28S	4.7
Human	18S	1.9
	28S	5.0