Maximum read length for Illumina sequencing platforms

Maximum supported read length
Illumina platforms and sequencing kits allow for a variety of sequencing applications. To ensure the highest level of quality, Illumina supports reads up to a certain length depending on the sequencing platform and SBS kit version; refer to the How many cycles of SBS chemistry are in my kit? support bulletin. It is possible to choose a longer read length during run setup in Local Run Manager (LRM) or the instrument control software. However, when the read length exceeds the supported length Illumina cannot guarantee maintaining high data quality.
Table 1. Maximum supported read length for sequencing platforms and SBS reagent kits.
* MO: Mid-output / HO: High-output ** Rapid Run
Maximum read length for index reads
  • Instrument control software: enter custom Index Read length during run setup for certain instruments, as shown below in Table 2.
  • LRM v2: enter up to 100 characters for the maximum index cycles (refer to the Local Run Manager 2: How to use a custom library prep kit support bulletin).
  • LRM v3: enter up to 20 characters, or use manual mode if you need between 20 and 100 bp.
  • To ensure sequencing quality of the Index Read, do not exceed the supported read length.
Table 2. Maximum individual index length for sequencing platforms.
*When setting up runs in Cloud mode, index length is limited to 10 bp.
**For index length between 20-100 bp, use manual mode as LRM v3 is limited to 20 bp
For any feedback or questions regarding this article (Illumina Knowledge Article #2826), contact Illumina Technical Support [email protected].
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