# Illumina RNA Prep Tagmentation (L) with Enrichment Input FAQs **What is the RNA input requirement?** The protocol is optimized for 10-100 ng of purified total RNA. Lower input amounts can reduce library yield. **Is the kit compatible with RNA from FFPE samples?** Yes, for FFPE samples with DV200 value <80% Illumina recommends increasing the number of PCR cycles to 17. **What are the optimal 260/280 and 260/230 ratios for the input RNA?** (Refer to the first informational row, the second and third are provided for context.)
SubstanceAbsorbance (nm)260/280 Ratio260/230 Ratio
Pure RNA280~2.02.0-2.2
EDTA, Carbohydrates, Phenol230<1.5<2.0
Guanidine HCl230<1.5<2.0
**What is the recommended quantitation method for input RNA?** RNA should be quantified with a fluorometric method specific for RNA. **Does input RNA need to be treated with DNase?** Yes, DNA should be removed by including a DNase treatment with the RNA isolation method for sample purity and accurate quantification. **What is the effect of residual DNA contamination?** DNA can interfere with accurate quantification of the sample. DNA contamination will also impact the sequencing data, increasing the background level of expression for all transcripts. \ \ \
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