How to Read a Certificate of Analysis (COA): A Complete Guide

Why Every Cannabinoid Consumer Needs to Know How to Read a COA

A Certificate of Analysis (COA) is the only objective, third-party verification of what is actually in a cannabinoid product. It is the document that separates a brand making claims from a brand proving them.

Yet most consumers have never read one — and most brands count on that. A COA published on a website looks credible whether it's from an accredited laboratory or a questionable one, whether it covers your specific batch or a generic sample from two years ago, and whether it tests for contaminants or only for potency.

This guide teaches you how to read every section of a full-panel COA, what each result means, what red flags to watch for, and how to use cbdDR's Batch Database to verify the specific product you purchased.

What Is a Certificate of Analysis?

A Certificate of Analysis is a document issued by an independent laboratory that reports the results of analytical testing performed on a specific sample. In the cannabinoid industry, a full-panel COA covers:

• Cannabinoid potency — the concentration of each cannabinoid present in the product
• Heavy metals — testing for lead, arsenic, mercury, and cadmium
• Pesticides — screening for agricultural chemical residues
• Residual solvents — testing for extraction solvent residues
• Microbials — testing for harmful bacteria, mold, and yeast

A COA that covers only cannabinoid potency is not a full-panel COA. Potency-only testing tells you what's in the product but not whether it's safe to consume.

Step 1: Verify the Laboratory

Before reading any results, verify the laboratory that issued the COA. This is the most important step and the one most consumers skip.

• ISO/IEC 17025 accreditation — the laboratory must hold this international accreditation, which verifies that its testing methods are scientifically sound, its equipment is calibrated, and its results are reliable. Accreditation is granted by independent accreditation bodies such as A2LA (American Association for Laboratory Accreditation) or PJLA. You can verify a laboratory's accreditation status directly on the accreditation body's website.
• Independence — the laboratory must be independent from the manufacturer. In-house testing or testing by a laboratory with financial ties to the brand is not acceptable.
• Scope of accreditation — verify that the laboratory's accreditation covers the specific tests reported on the COA (potency, metals, pesticides, etc.). Some laboratories are accredited for some tests but not others.

Step 2: Verify the Batch or Lot Number

The COA must reference the specific batch or lot number of the product you purchased. This is non-negotiable.

A COA from a different batch tells you nothing about your product. Cannabinoid concentrations, contaminant levels, and safety parameters can vary between batches — especially in non-standardized products. Always match the batch number on your product label to the batch number on the COA.

If a brand cannot provide a batch-specific COA for your product, that is a significant red flag.

Step 3: Read the Cannabinoid Potency Panel

The potency panel reports the concentration of each cannabinoid detected in the sample, typically expressed in mg/g or mg/mL and as a percentage of total weight.

What to look for:

• Label claim accuracy — the reported CBD (or CBG, CBN, CBC) concentration should match the label claim within a reasonable tolerance (typically ±10–15%). Significant deviation indicates poor standardization.
• THC status — for zero-THC products, THC should be reported as ND (non-detected) or below the laboratory's limit of detection (LOD). Confirm the LOD is stated on the COA.
• Total cannabinoid profile — a quality broad spectrum product should show meaningful concentrations of multiple cannabinoids, not just CBD with trace amounts of others.
• THCA and Δ94-THC — both should be reported separately. Some products pass THC limits on Δ94-THC alone but contain THCA that converts to THC upon heating.

Step 4: Read the Heavy Metals Panel

Hemp is a bioaccumulator — it absorbs heavy metals from soil with exceptional efficiency. This makes heavy metals testing non-negotiable for any hemp-derived product.

The four metals tested in a standard panel are:

• Lead (Pb) — action limit typically ≤0.5 μg/g
• Arsenic (As) — action limit typically ≤1.5 μg/g
• Mercury (Hg) — action limit typically ≤0.1 μg/g
• Cadmium (Cd) — action limit typically ≤0.5 μg/g

Results should be reported as ND (non-detected) or as a specific concentration below the action limit. Any result at or above the action limit is a failing result and the product should not be consumed.

Step 5: Read the Pesticides Panel

The pesticides panel screens for agricultural chemical residues. A comprehensive pesticides panel covers 60–100+ individual compounds. Be cautious of COAs that report only a small number of pesticides — this may indicate a limited screening rather than a comprehensive panel.

All results should be ND (non-detected) or below established action limits. Any detected pesticide at or above its action limit is a failing result.

Step 6: Read the Residual Solvents Panel

Cannabinoid extraction uses solvents — ethanol, CO₂, butane, propane, or others. Residual solvent testing verifies that extraction solvents have been adequately removed from the finished extract.

Key solvents to check:

• Ethanol — most common extraction solvent; should be below 5,000 ppm
• Butane/Propane — should be ND or below action limits
• Benzene — a known carcinogen; must be ND
• Heptane — action limit typically ≤5,000 ppm

Step 7: Read the Microbials Panel

Microbial testing screens for harmful biological contaminants including:

• Total Yeast and Mold Count (TYMC)
• Total Aerobic Count (TAC)
• E. coli — must be absent
• Salmonella — must be absent
• Aspergillus species — must be absent

All results should pass established action limits. Microbial contamination is a serious safety concern, particularly for immunocompromised individuals.

COA Red Flags: What to Watch For

• ⚠️ No batch or lot number — the COA cannot be tied to your specific product
• ⚠️ Non-accredited laboratory — results cannot be independently verified for methodological soundness
• ⚠️ Potency-only testing — no heavy metals, pesticides, solvents, or microbials
• ⚠️ COA dated more than 12 months ago — may not represent current production batches
• ⚠️ Significant potency deviation from label claim — indicates poor standardization
• ⚠️ THC detected above ND — for zero-THC products, any THC detection is a failing result
• ⚠️ Missing panels — a COA that omits any standard panel without explanation

Frequently Asked Questions

What does ND mean on a COA?

ND stands for Non-Detected — meaning the compound was not detected at or above the laboratory's limit of detection (LOD). The LOD should be stated on the COA. ND does not mean zero; it means below the detectable threshold.

How do I verify a laboratory's ISO/IEC 17025 accreditation?

Visit the website of the accreditation body listed on the COA (e.g., A2LA at a2la.org, PJLA at pjlabs.com) and search for the laboratory by name. Accreditation status, scope, and expiration date are publicly searchable.

How often should a brand test its products?

Every batch should be tested independently before release. A brand that tests only periodically or only tests reference samples is not practicing true batch-level quality control.

Verify Your cbdDR Product

cbdDR publishes batch-specific COAs for every product in our Batch Database. Every COA is issued by an ISO/IEC 17025-accredited independent laboratory and covers the full panel — potency, heavy metals, pesticides, residual solvents, and microbials. Match your batch number to your COA and verify every result yourself.

We don't ask for trust. We provide proof. Access the Batch Database →

Related Articles

• Why Standardization Is the Most Important Word in Cannabinoid Wellness
• What Are Standardized Cannabinoid Formulations?
• The Endocannabinoid System: How Your Body Regulates Itself
• cbdDR Batch Database — All COAs Published
• The cbdDR Cannabinoid Science Guide — Free Download

References

• Bonn-Miller MO, et al. (2017). Labeling Accuracy of Cannabidiol Extracts Sold Online. JAMA, 318(17), 1708–1709. PMID: 29114823
• ISO/IEC 17025:2017. General requirements for the competence of testing and calibration laboratories. International Organization for Standardization.
• U.S. Hemp Authority Certified Good Manufacturing Practices Standard. (2020).
• American Association for Laboratory Accreditation (A2LA). ISO/IEC 17025 Accreditation Program.

cbdDR does not make disease treatment claims. All formulations are hemp-derived and federally legal under the 2018 Farm Bill. Consult a qualified healthcare provider for medical advice.