> 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/microarray/general/microarray-general-troubleshooting-list/000003735.md).

# How to recoat Infinium BeadChip with XC4

Occasionally, a BeadChip may exhibit scanning issues caused by artifacts such as bubbles, dust, or debris trapped beneath the XC4 coating. In such cases, recoating the BeadChip can help restore image quality and improve overall scan performance.

To recoat the BeadChip with XC4, follow the steps below:

1. Remove the existing XC4 coating by soaking the BeadChip in 100% ethanol (EtOH) for approximately 10 minutes, or until the coating has completely dissolved. Successful removal is indicated by the disappearance of the shiny, iridescent surface.
2. Once the coating has been removed, proceed to the **“Wash and Coat BeadChips”** step in the protocol (following the XStain process) and complete the wash, XC4 coating, and drying steps as described. The use of staining rack and wash dish is recommended for optimal result.
3. Prior to scanning, clean the sides and underside of the BeadChip using a lint-free wipe lightly moistened with 70% ethanol to remove any residual XC4.
4. Finally, ensure that the BeadChip is properly seated flat on the iScan beadchip carrier before rescanning, as improper positioning may affect scan quality.

**Additional Resources:**

* Illumina Knowledge [Recommendations for Infinium Array XC4 reagent use and storage](/microarray/general/microarray-general-reference_material-list/000001517.md).

\
\
\ <br>

|                                                                                                                                                                                                                                                                                                                                                                   |
| :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |
| *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)*.* |


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://knowledge.illumina.com/microarray/general/microarray-general-troubleshooting-list/000003735.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.