Molecular biology experiments such as reverse-transcriptase PCR (RT-PCR) use RNA populations to create complementary DNA (cDNA). To assess RNA concentration and purity, methods such as UV spectroscopy are traditionally used. In this method, the absorbance of RNA is measured at 260 and 280 nm and a ratio of the two (A260/A280) is used to assess RNA purity. Highly purified RNA samples have an A260/A280 ratio of 1.8 to 2.1.

The following table outlines the recommended range of input RNA for RT-PCR.