---
title: "Can I check if my Fiber-seq labeling was done correctly before preparing an LRS library?"
slug: "can-i-check-my-fiber-seq-labeling-was-done-correctly"
updated: 2026-10-20T20:20:30Z
published: 2026-10-20T20:20:30Z
canonical: "support.epicypher.com/can-i-check-my-fiber-seq-labeling-was-done-correctly"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://support.epicypher.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Can I check if my Fiber-seq labeling was done correctly before preparing an LRS library?

Yes! Before investing in deep sequencing, you can confirm that your Fiber-seq labeling worked as expected using Plasmidsaurus’s [**Fiber-seq for 6mA**](https://plasmidsaurus.com/faq/custom#how-do-i-request-fiber-seq-services-for-the-epicypher-partnership-for-either-qc-of-6ma-or-whole-genome)**,** developed in partnership with EpiCypher. First, assess the quality of your sample gDNA as described in the [manual](https://www.epicypher.com/wp-content/uploads/fiber-seq-kit-manual_v1.pdf) and determine the quantity recovered. You will need at least 300ng of gDNA to assess labelling, so be sure to review the input recommendations of your LRS provider and confirm you will have enough gDNA leftover after the labelling QC sequencing for deeper sequencing. After confirming you will have enough gDNA remaining, you can submit ≥300ng of your purified gDNA to Plasmidsaurus for their **Fiber-seq QC for 6mA** service.

The Plasmidsaurus **Fiber-seq QC for 6mA** service performs shallow sequencing (~100 Mb) on an ONT PromethION instrument. It is designed to assess whether 6mA labeling is present in your sample and distributed along individual fibers as expected. EpiCypher routinely uses this service as a QC step for internal Fiber-seq projects.

Plasmidsaurus will provide a report of the average percent 6mA in your sample. If the value is within the expected range (generally 4-10%), we recommend performing a brief downstream analysis (for instructions, see [this article](/v1/docs/how-do-i-analyze-my-fiber-seq-qc-sequencing-data)) to confirm that the overall 6mA distribution and chromatin features look biologically reasonable before proceeding to deep sequencing.