> 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/instrumentation/novaseq-x-x-plus/instrumentation-novaseq-x-x-plus-reference_material-list/000008320.md).

# RTA4 Q Score Bin Ranges on the NovaSeq X/X Plus

**Background**

The NovaSeq X/X Plus utilizes Real Time Analysis v4 (RTA4) for base calling and quality scoring. There are three Q score bins used on the NovaSeq X/X Plus, and these Q score calls are reported as an average for the range of called scores. Please see below for the relevant Q Score Bins and Ranges depending on Control Software version.

*Control Software v1.3*

<table data-header-hidden><thead><tr><th valign="top"></th><th valign="top"></th></tr></thead><tbody><tr><td valign="top">Bin</td><td valign="top">Q Score Range</td></tr><tr><td valign="top">2</td><td valign="top">NoCall, 0-2</td></tr><tr><td valign="top">9</td><td valign="top">3-17</td></tr><tr><td valign="top">24</td><td valign="top">18-29</td></tr><tr><td valign="top">40</td><td valign="top">30+</td></tr></tbody></table>

*Control Software v1.2 and v1.2.2*

<table data-header-hidden><thead><tr><th valign="top"></th><th valign="top"></th></tr></thead><tbody><tr><td valign="top">Bin</td><td valign="top">Q Score Range</td></tr><tr><td valign="top">2</td><td valign="top">NoCall, 0-2</td></tr><tr><td valign="top">12</td><td valign="top">3-17</td></tr><tr><td valign="top">24</td><td valign="top">18-29</td></tr><tr><td valign="top">40</td><td valign="top">30+</td></tr></tbody></table>

For more information on changes to Q Score bins with Control Software v1.2, please see the following Illumina article:

[NovaSeq X v1.2 software enables sequencing with 80% of bases >= Q40](https://www.illumina.com/science/genomics-research/articles/data-quality-q-scores.html)

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #8320), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000008320%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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