# RTA4 Q Score Bin Ranges on the MiSeq i100 Series

**Background**

The MiSeq i100 Series utilizes Real Time Analysis v4 (RTA4) for base calling and quality scoring. There are three Q score bins used on the MiSeq i100 Series, 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.

MiSeq i100 Control Software version 1.1 and later

| **Quality Score Bin** | **Quality Score Range** |
| --------------------- | ----------------------- |
| 2                     | NoCall, 0-2             |
| 9                     | 3-17                    |
| 23                    | 18-29                   |
| 38                    | 30+                     |

MiSeq i100 Control Software version 1.0

| **Quality Score Bin** | **Quality Score Range** |
| --------------------- | ----------------------- |
| 2                     | NoCall, 0-2             |
| 12                    | 3-17                    |
| 24                    | 18-29                   |
| 38                    | 30+                     |

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #9540), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000009540%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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