Evaluation of a novel approach for the measurement of RNA quality

Measurement of SDV for a panel of intentionally degraded RNA samples ranged from 0 for intact RNA to 37 for degraded RNA, with corresponding RIN values ranging from 10 to 4 for the same set of samples. SDV and RIN scales both demonstrated comparable discrimination between differently treated samples (RIN 10 to 7, SDV 0 to 15), with the SDV exhibiting better discrimination at higher degradation levels. Increasing SDV values correlated with a decrease in microarray sample labelling efficiency and an increase in numbers of differentially expressed genes.The ScreenTape？ platform is comparable to the Bioanalyzer platform in terms of reproducibility and discrimination between different levels of RNA degradation. The robust nature of the SDV metric qualifies it as an alternative metric for RNA sample quality control, and a useful predictor of downstream microarray performance.The use of microarray technology has revolutionised the fields of molecular biology and genetics. However, concerns have been raised over the numerous potential sources of variation that can affect assay consistency and data quality [1,2]. Previous studies have highlighted RNA integrity as one source that has a major effect on microarray data quality [3-5].To date, no single RNA integrity metric has been adopted universally by the research community. RNA quality is commonly determined by several different techniques, including the ribosomal peak ratio (eukaryotic 28s/18s rRNA peak intensity ratio) [6], RIN [7], 5'/3' transcript signal intensity ratio determined by qRT-PCR or microarray analysis [8] and other quality indices [9].RNA purity is assessed routinely by measuring the OD260 nm/OD280 nm ratio [6,10,11] of a sample. However, this metric yields no information about RNA integrity. Molecular biologists have therefore relied on the technique of gel electrophoresis, which provides a reproducible separation of ribosomal RNA (rRNA) molecules to derive overall sample RNA integrity. Currently, such conv