A COA reports measurements from a sample. It is not a certificate of medical effectiveness or a guarantee about every item.
First, Match the Sample
A certificate of analysis, or COA, records results of laboratory tests on a sample. Begin with the product name, sample description, and batch or lot identifier. Compare them with the package.
A report for an ingredient, another flavor, or an older batch may not describe the finished item in front of you. Note both the testing date and the date the report was issued.
Next, Read the Units
Results may be listed as a percentage, milligrams per gram, milligrams per milliliter, or milligrams per unit. Keep the units attached to the number.
For example, 1% by mass is 10 mg per gram. Converting that into milligrams per bottle requires the mass of the bottle’s contents. Do not assume a liquid’s volume in mL is automatically its mass in grams.
Use the label guide to separate total CBD from an amount per serving.
Detection Limits and Missing Tests
Look for the report’s legend. “ND” commonly means not detected under the method’s stated limit. “Not tested” means something different. If a compound or contaminant is absent from the report, ask whether it was measured.
A cannabinoid potency panel and a contaminant panel answer different questions. Look for the actual results and reporting limits for each test, rather than relying on one broad “pass” headline.
A Practical Reading Checklist
This checklist helps you read a document. Completing it does not certify a product.
Understand the Limits of Testing
NIST works to improve the accuracy and comparability of CBD and THC measurements. A laboratory name alone does not show whether its method fits the sample.[1]
The FDA has identified concerns about inaccurate CBD amounts and contaminants in consumer products.[2] Ask the manufacturer or laboratory about unexplained results. A COA cannot prove that a product treats a health condition.
A COA Is a Report With a Scope
Think of a certificate of analysis as answers to the questions the laboratory was asked to measure. Before reading a “pass” or a potency number, find the sample description and the list of tests. Those tell you what the report can actually address.
The units and limits belong to the result. A result without its basis can be misunderstood even when the laboratory measured it accurately. A helpful report also explains abbreviations and identifies where a conclusion depends on a particular specification.
A Report That Looks Complete at First
Imagine a package with batch B204 and a report for B203. The report may be detailed and recent, but it has not yet been matched to your package. Or imagine a matching report with cannabinoid results and no contaminant panel. You have potency information, while the contaminant question remains open.
Neither situation requires guessing. Record the missing match or test and ask for the appropriate finished-product report. A precise question is easier to answer than a broad request for proof that something is “good quality.”
Questions Readers Often Ask
Does an accredited laboratory make every possible claim true?
Laboratory credentials and a suitable method matter, but the report still concerns a particular sample and test scope. Read what was measured and which conclusion those measurements support.
What is the difference between ND and not tested?
ND is a result interpreted under a stated limit. Not tested means the question was not measured. A blank field needs clarification rather than an assumption of zero.
Can I check whether CBD helps a condition using a COA?
No. A COA concerns composition and other measured properties. Controlled clinical evidence addresses a health outcome. Keep the two records separate.
Sources & Further Reading
- NIST: Helping Labs Achieve Accurate THC and CBD Measurements ↗
- FDA: What to Know About Cannabis-Derived Products, Including CBD ↗
Sources checked October 5–6, 2026. This page is for general education. No medical review or endorsement is implied. Read the editorial policy.