> 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-reference_material-list/000005602.md).

# DMAP File Availability and Retention Policy for Infinium Arrays

Each Infinium BeadChip is associated with a unique DMAP file, which is generated at the time of manufacturing. This file contains information about the location and identity of each beadtype on the array. During scanning, these beadtype locations are combined with the measured signal intensities to generate .idat files for each sample. As such, the DMAP file is essential for data processing and analysis of Infinium BeadChips.\
The availability of DMAP files is directly linked to theshelf life and expiration date of the associated BeadChip. Users are advised to download and securely store DMAP files prior to the expiration date printed on the BeadChip packaging. Downloading the file in advance helps mitigate the risk of losing access to this critical file. For detailed information on shelf life and expiration timeline across different Infinium Array types, refer to [Infinium BeadChips Shelf Life and Expiration Timeline](https://github.com/illumina-swi/illumina-knowledge/tree/master/articles/Knowledge/Infinium-BeadChips-Expiration/README.md).## DMAP File Availability and Retention Policy

Illumina guarantees retention and access to DMAP files for up to two (2) years from the date of manufacture. If a DMAP file is not downloaded within this two-year period, it will no longer be available, and scanning and analysis of the associated BeadChip cannot be performed.

Historically, DMAP files were occasionally accessible beyond the two-year retention period, however, such access was not guaranteed. As part of updated file management practices, Illumina has transitioned to a system in which DMAP files are permanently deleted and no longer retained beyond the defined two-year retention window.

This policy change took effect on August 2, 2021, and applies to all Infinium array types, including:

* Commercial arrays
* Semi-custom arrays
* Custom arrays
* Consortia products

This update was implemented to improve the performance, reliability, and efficiency of DMAP file access and downloads.

**Table 1.** DMAP file retention timelines based on BeadChip shelf life.

| **Infinium BeadChip Type**                                               | **BeadChip Shelf Life** | **DMAP Retention after Expiration** | **Total DMAP Retention from Manufacture Date** |
| ------------------------------------------------------------------------ | ----------------------- | ----------------------------------- | ---------------------------------------------- |
| <p>HD, LCG, XT, LCG+PGx,</p><p>EX Genotyping, EX Methylation, EX+PGx</p> | 12 months               | 12 months                           | 2 years                                        |
| 24-sample HTS BeadChips                                                  | 18 months               | 6 months                            | 2 years                                        |
| <p>Multiple 8-sample and 12-sample BeadChips<br></p>                     | 18 months               | 6 months                            | 2 years                                        |

For questions or concerns, contact Illumina Technical Support at <techsupport@illumina.com>.\
\
\
\ <br>

|                                                                                                                                                                                                                                                                                                                                                                   |
| :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |
| *For any feedback or questions regarding this article (Illumina Knowledge Article #5602), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000007091%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-reference_material-list/000005602.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.