# Trimming output problem

**URL:** <https://forum.qiime2.org/t/trimming-output-problem/29631>\
**Category:** User Support\
**Created:** [March 20, 2024, 6:57am UTC](https://forum.qiime2.org/t/trimming-output-problem/29631 "2024-03-20T06:57:06Z")\
**Posts on this page:** 1\
**Showing post:** 14

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**Author:** ![SoilRotifer](https://forum.qiime2.org/user_avatar/forum.qiime2.org/soilrotifer/32/21071_2.png) [@SoilRotifer](https://forum.qiime2.org/u/SoilRotifer)\
**Post date:** [March 26, 2024, 12:32am UTC](https://forum.qiime2.org/t/trimming-output-problem/29631/14 "2024-03-26T00:32:19Z")

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Thanks for sharing these @Liviacmg. I think for those samples, in which you're losing more sequences, appears to be due to losing proportionally more due quality filtering rather than chimera removal. The drop from denoised to non-chimeric isn't as much of a drop as the quality filtering. This could probably be helped by truncating a little more.

Another option is to adjust the `--p-min-fold-parent-over-abundance` to `8` or `16`. I wouldn't suggest any higher than that. This is based on the following:

- [Edgar 2016](https://www.biorxiv.org/content/10.1101/081257v1.full)
- [usearch uchime\_denovo settings](https://www.drive5.com/usearch/manual/cmd_uchime3_denovo.html)
  - [abundance skew](https://www.drive5.com/usearch/manual/abundance_skew.html)

- [DADA2 Github thread](https://github.com/benjjneb/dada2/issues/1042#issuecomment-648400339)

_Some of these refer to usearch / vsearch parameters, which are analogous to this DADA2 parameter. Much of this is explored in the github thread._

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