# Multi\_chain and extra\_chains

**URL:** <https://discourse.scverse.org/t/multi-chain-and-extra-chains/2028>\
**Category:** scirpy\
**Created:** [January 26, 2024, 10:14am UTC](https://discourse.scverse.org/t/multi-chain-and-extra-chains/2028 "2024-01-26T10:14:51Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![m21camby](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.scverse.org/m21camby/32/932_2.png) [@m21camby](https://discourse.scverse.org/u/m21camby)\
**Post date:** [January 26, 2024, 10:14am UTC](https://discourse.scverse.org/t/multi-chain-and-extra-chains/2028/1 "2024-01-26T10:14:51Z")

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Hi, when I check the data after read\_10x\_vdj, I see multi\_chain column shows false while extra\_chains is filled with something like: [{“c\_call”: “IGLC1”, “consensus\_count”: 27, “d\_call”: null, “duplicate\_count”: 1, “j\_call”: “IGLJ1”, “junction”: null, “junction\_aa”: null, “locus”: null, “productive”: false, “v\_call”: null}]  
If I understood correctly, extra\_chains should be blank if multi\_chain is false. Could you explain this?

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**Author:** ![grst](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.scverse.org/grst/32/17_2.png) [@grst](https://discourse.scverse.org/u/grst)\
**Post date:** [January 26, 2024, 10:38am UTC](https://discourse.scverse.org/t/multi-chain-and-extra-chains/2028/2 "2024-01-26T10:38:17Z")

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Only productive chains are counted towards `multi_chain`. The chain in your example is non-productive.

As a side note if you still have the `extra_chains` column, you are likely using an outdated version of scirpy. Consider upgrading to the latest version with an improved data structure.