# Illumina RNA Prep Tagmentation (L) with Enrichment Sequencing FAQs

The following are commonly asked questions for sequencing Illumina RNA Prep Tagmentation (L) with Enrichment Sequencing libraries.

**What is the recommended read length and number of reads per sample?**

* Illumina recommends a paired-end run of 76 cycles per read (2x76) with 10 cycles for each index read (Read 1: 76, Index 1: 10, Index 2: 10, Read 2: 76) regardless of the enrichment probe panel or sample input type.
* Libraries can be sequenced with longer read lengths (2x101, 2x126 or 2x151) if a lab would like overlapping reads or additional raw coverage, but it is not required.

**What are the advantages of performing paired-end sequencing of RNA libraries?**\
Paired-end sequencing helps with data alignment, discovery of novel transcripts, and identification of PCR duplicates.

**What are the suggested loading concentrations for the various sequencers?**\
The Illumina RNA Prep with Enrichment [Reference Guide](https://support.illumina.com/downloads/illumina-rna-prep-reference-guide-1000000124435.html) includes select loading concentration recommendations. For other sequencers and panels, consult the denature and dilution guide of the sequencer that will be used.

**Can libraries prepared with this kit be pooled with other library types for sequencing?**\
This is not supported and results are not guaranteed.

**What is the recommended sequencing depth/number of reads per sample?**\
Generally, 3-25 million reads per sample, depending on the panel. The read requirement depends on the enrichment panel used and data needs for each experiment, and may need to be optimized.

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #3295), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000003295%20-%20Library%20Preparation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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