Quality Control/Quantity Assessment

RNA

Unless the PI specifically requests otherwise (in the Special Instructions of the submission sheet), the following steps will be performed as part of RNA QC/QA:

1. The sample is quantified in 10mM Tris on a Spectrophotometer. In addition to concentration, this instrument reports the 260/280 absorption ratio, which can be an important indicator of hidden contaminants.
2. The sample is then analyzed on an Agilent 2100 Bioanalyzer. The electropherogram it produces makes it easy to spot certain contaminants or degradation, and to calculate the 28s:18s ratio (Sample Report).

The primary determinant of RNA quality in the WCIMC is the RNA Integrity Number (RIN), produced by a recent upgrade of the Bioanalyzer software. This is a number ranging betweeen 1 (degraded) and 10 (intact). For microarray work, we recommend that all samples have a RIN of at least 7.0. The RIN is superior to other single measures of quality (such as the 28s:18s ratio) because it considers the entire electropherogram, rather than just one or two points. There are occasions, however, where the software refuses to assign a RIN. This does not mean that your RNA is bad! In this case, we advise investigators to examine the electropherogram, 260/280 ratio, and 28s:18s ratio to make a quality determination. If you need help with such a case, please contact us.