The ISOLATE II Biofluids RNA Kit isolates total RNA with minimal amounts of genomic DNA contamination using the supplied Genomic DNA Removal Column. However, additional DNase I treatment may be required in certain cases e.g. the amount of genomic DNA in the sample exceeds the capacity of the Genomic DNA Removal Column, or performing a highly sensitive application. The on-column DNase I digestion results in minimal residual DNA, undetectable in most downstream applications. For the most sensitive applications, DNA digestion in solution is recommended to eliminate even traces of contaminating DNA. Stringent RNase control is needed as well as RNA repurification to remove buffer, salts, DNase I and digested DNA.