# How to recoat Infinium BeadChip with XC4

Occasionally, a BeadChip may have scanning issues due to bubbles, dust, or debris trapped under the XC4 coating.

To recoat the BeadChip with XC4, follow these steps:

1. Remove the XC4 coating by soaking in 100% EtOH for 10 minutes, or until the XC4 dissolves. This is indicated by the loss of the shiny, iridescent coating.
2. Proceed to the "Wash and Coat BeadChips" step which comes after XStain. Follow the "Wash and Coat BeadChips" protocol through the XC4 coating and drying. It is recommended to use the staining rack and wash dish for these steps.
3. Before scanning, clean the sides and the underside of the BeadChip with a non-lint wipe sprayed with 70% ethanol.
4. Make sure the BeadChip is seated flat on the iScan carrier before rescanning the BeadChip.

For additional information, see Illumina Knowledge "[Recommendations for Infinium Array XC4 reagent use and storage](https://knowledge.illumina.com/microarray/general/microarray-general-reference_material-list/000001517)."

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #3735), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000003735%20-%20Microarray%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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