RNAkvalitet

RNAkvalitet refers to the overall suitability of RNA for use in molecular analyses. It primarily concerns RNA integrity—the degree to which RNA molecules remain intact—and RNA purity—the absence of contaminants such as proteins, phenol, salts, and DNA. High RNAkvalitet is essential for reliable results in techniques like RNA sequencing, qPCR, Northern blotting, and microarray analyses.

Quality is typically assessed with both integrity and purity metrics. Integrity is measured by electrophoretic methods or capillary systems that produce an RNA integrity profile and a score such as the RNA Integrity Number (RIN) from 1 to 10, with 10 representing intact RNA. DV200 is another metric describing the percentage of fragments longer than 200 nucleotides. The 28S:18S ribosomal RNA ratio can indicate degradation in many eukaryotic samples. Purity is assessed by spectrophotometric ratios: A260/280 around 2.0 indicates low protein contamination, and A260/230 values above 2.0 suggest low organic or salt contamination.

Typical requirements vary by application. RNA-seq and most quantitative methods usually require high-quality RNA, generally RIN values above 7–8, though certain sample types, like FFPE tissue, may be acceptable with lower RINs if DV200 is adequate. Degraded RNA may still be usable for targeted assays but can bias transcript representation and shorten reads.

Factors affecting RNAkvalitet include tissue type, time from collection to stabilization, RNase exposure, storage conditions, freeze–thaw cycles, and the chemistry of extraction. Handling should be conducted in RNase-free environments using validated protocols and materials.

Improving RNAkvalitet involves rapid stabilization after collection (e.g., RNAlater or snap freezing), maintaining cold-chain, minimizing handling time, DNase treatment to remove DNA, and using high-quality extraction kits. When quality is insufficient, results should be interpreted with caution, or degraded samples may be restricted to suitable assays.