Quality & Lab ValuesEinsteiger7 min 4 sourcesUpdated: 2026-03-26

Reading a COA correctly

This is how you interpret lab reports on potency, terpenes, and contaminants without falling into marketing traps.

Required fields

Batch, date, method

Watch for

LOQ/LOD and units

Warning sign

Incomplete contaminant list

Key points

  • A good COA is batch-specific, current, and methodologically traceable.
  • Potency alone is not enough to make quality claims.
  • Threshold values and detection limits must be read in context.
1

What you check first

Check first: Is the batch number identical to your product? Is the analysis date current?

Without this match, the COA is worthless — it could describe any other product.

Checklist

  • Batch number identical to the product
  • Current analysis date
  • Methods and units clearly stated
2

Why a COA changes your purchase decision

A COA shows you what you're really getting — potency, terpenes, contaminants.

Without a lab report, every quality claim is marketing, not fact.

3

Assessing contaminants correctly

Individual traces below the threshold must be assessed differently than systematic anomalies.

What matters: Are detection limits (LOQ/LOD) stated? If they're missing, the result is not comparable.

4

Relevant in SecretLeaf when

you're buying a product and want to verify that the claims are correct

you're comparing batches and want to understand why quality varies

you want to decide whether a supplier can be trusted

5

What you should specifically do

Checklist

  • Match the batch number on the COA against the one on the packaging — always, no exceptions
  • Check: Is the contaminant list and measurement method complete? If not, ask or switch suppliers
  • Store COAs by batch in your grow log — that's the only way you can compare later

Frequently asked questions

How do I recognize a good COA?
Check: (1) lab accreditation (ISO 17025?), (2) methods documented (GC-MS? HPLC?), (3) result uncertainty stated, (4) signature of the lab director.
Can a COA be falsified?
Yes, easily. Only labs with independent verification (e.g. proficiency tests) are trustworthy.

Sources

→ Full register
  1. 1

    Gas and Liquid Chromatography Methods for Cannabinoid Analysis

    Journal of Chromatography A · 2024

    Open ↗
  2. 2

    Terpene Profiling and Quantification in Cannabis

    Analytical Chemistry · 2023

    Open ↗
  3. 3

    AOAC Official Methods of Analysis: Cannabis Testing Protocols

    AOAC International · 2024

    Open ↗
  4. 4

    ISO/IEC 17025: General Requirements for Testing Laboratories

    ISO · 2017

    Open ↗

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Editorial note: The content is for knowledge and education. Regional law, medical questions and regulatory requirements must always be checked separately by qualified professionals.