> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/library-preparation/dna-enrichment-based-library-prep/library-preparation-dna-enrichment-based-library-prep-faq-list/000009492.md).
# Sequencing FAQ for Illumina FFPE DNA Prep with Exome 2.5 Enrichment
**Which instruments does Illumina support for sequencing?**
* NovaSeq X series : 1.5B
* NovaSeq 6000: SP, S1, and S2
* NextSeq 2000: P3 and P4 (XLEAP)
**What is the recommended number of samples per run?**
Similar information can also be found in the [Denature and Dilute Protocol Generator](https://support-docs.illumina.com/IN/dnd-wizard/Content/dnd/landing.htm). \*\*What is the targeted reads per sample to achieve 150X normal/500X tumor. Is it 28M reads to normal and \~72M reads to tumor? (M = million)\*\*28M for Normal, and \~100M for Tumor single-end reads.
\*\*Is PhiX spike in recommended?\*\*Spike-in of PhiX is not required. However, customers can follow the general guidelines of spiking in 1-2% PhiX for additional sequencing metrics, if desired.
\*\*What is the recommended read length?\*\*2x151 with 10 bp indexes.
**What is the recommended loading concentration for all supported Illumina Platforms?**
* Note: users may need to optimize loading concentrations, though the following can be used as a general starting point:
* NextSeq 2000: 750 pM
* NovaSeq 6000 (SP, S1, S2): 500 pM (0.5 nM) pooled library concentration; 100 pM final library concentration. Must use Standard loading so one pool goes into both lanes to achieve sequencing depth requirements
* NovaSeq X series (1.5B only): 40 pM final loading concentration. One pool goes into both lanes to achieve sequencing depth requirements
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| *For any feedback or questions regarding this article (Illumina Knowledge Article #9492), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000009492%20-%20Library%20Preparation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
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