RNA integrity number: towards standardization of RNA quality assessment for better reproducibility and reliability of gene expression experiments

Excerpt

Good RNA quality assessment is considered one of the most critical elements to obtain meaningful gene expression data via microarray or real-time PCR experiments. Advances in microfluidic technology have improved RNA quality measurements by allowing a more detailed look at patterns of RNA degradation via the use of electrophoretic traces. However, the interpretation of such electropherograms still requires a certain level of experience and can vary from one researcher to the next. The 'RNA integrity number' (RIN) algorithm is introduced to assign a user-independent integrity number to each RNA sample. The RIN has been developed using neural networks by 'teaching' this algorithm with a large number of RNA integrity data. The RIN score, based on a quality numbering system from 1 to 10 (in ascending quality), facilitates the classification of RNA samples to be used in the context of the gene expression workflow. It was found that the RIN is more reliable than the ribosomal ratio when assessing the integrity of RNA samples. The RIN is shown to be largely independent of RNA concentration, independent of instrument (Agilent 2100 bioanalyzer), and most importantly independent of the origin of the RNA sample. Using the RIN, researchers can work towards standardization of RNA integrity measurement, ensuring reproducibility and reliability of gene expression experiments. …