A Certificate of Analysis, commonly shortened to COA, is a laboratory report showing what was measured in a sample. For cannabinoid materials, this commonly includes cannabinoid content and may also include tests for contaminants or other quality parameters.
A COA only applies to the sample that was tested. It is therefore important to check that the product, batch and laboratory information on the report match the material being evaluated.
What does a COA contain?
Sample identification
Information such as the product name, sample description and batch or lot number.
Laboratory information
The laboratory that performed the testing, report number and relevant testing dates.
Test method
The laboratory technique or analytical method used to perform the measurement.
Results
The measured concentrations or pass and fail results for the substances included in the test.
How cannabinoid results are presented
Common COA terminology
Not detected
The substance was not detected above the laboratory's applicable detection threshold. ND does not necessarily mean exactly zero.
Limit of detection
The lowest level at which the laboratory can reliably detect that a substance is present.
Limit of quantification
The lowest level at which the laboratory can reliably report how much of the substance is present.
Pass or fail
Indicates whether a result meets a predefined specification or limit used for that test.
Common types of laboratory tests
Cannabinoid content
Measures how much of each tested cannabinoid is present, such as CBD, CBG, CBN, THC or their acidic forms.
Heavy metals
Checks for potentially harmful metals such as lead, cadmium, arsenic and mercury.
Residual solvents
Tests for solvents that may remain after extraction, purification or other manufacturing processes.
Microbiological testing
Looks for microorganisms such as bacteria, yeast, mould or specific pathogens that may indicate contamination.
Mycotoxins
Tests for toxic compounds produced by certain moulds, including commonly monitored aflatoxins and ochratoxin A.
Pesticides
Screens for pesticide residues that may remain from cultivation or previous handling of plant-derived material.
Not every COA includes every type of test. A cannabinoid content report, for example, does not automatically mean that the material was also tested for pesticides, heavy metals, residual solvents or microorganisms.
Laboratory accreditations and quality standards
Having a COA is already valuable because it provides actual laboratory data about the tested sample. Additional laboratory accreditations and recognised quality systems can provide extra confidence that the testing is performed under controlled procedures and that the laboratory has demonstrated competence in particular areas.
ISO/IEC 17025
A widely recognised accreditation standard for testing laboratories. It provides additional assurance that the laboratory has demonstrated technical competence for specified analytical activities.
Scope of accreditation
An accredited laboratory may not have every test covered. The accreditation scope shows which specific methods or analyses are included.
GMP and GLP
GMP and GLP are broader quality frameworks used in manufacturing and laboratory work. They can provide additional quality assurance, but serve a different purpose from ISO/IEC 17025 laboratory accreditation.
A COA does not need an accreditation logo to contain useful analytical information. Accreditation should be viewed as an additional quality indicator rather than the basic requirement that makes a COA useful.
Matching a COA to the material
Check the product identity
The product or material named on the COA should match the material being supplied.
Match the batch number
Where batch or lot numbers are used, the identifier on the COA should match the material.
Check the dates
Review when the sample was received, tested and reported to confirm that the document reasonably relates to the batch.
Verify the laboratory
Check that the laboratory is clearly identified. Report numbers, signatures, QR codes or online verification may provide additional confirmation.
What a COA can and cannot show
What it can show
A COA provides analytical evidence about the specific sample that was tested. It can show cannabinoid content and any other parameters included in the laboratory analysis.
What it cannot automatically prove
A COA does not automatically prove that every unit in a batch is identical, that untested contaminants are absent or that the product is legal in every jurisdiction.
Why COAs matter
Verify composition
Laboratory testing provides an objective check of the cannabinoid composition or other specifications claimed for the material.
Check batch consistency
Comparing COAs between batches can help identify changes in concentration, purity or other tested characteristics.
Assess quality
A suitable testing panel can help identify contamination and provide useful information when evaluating suppliers or incoming materials.
Support compliance
Analytical results can help determine whether measured cannabinoids or contaminants fall within specifications or applicable regulatory limits.
A COA provides laboratory evidence, not a universal legal approval. Compliance still depends on the product, jurisdiction, applicable limits and the specific tests that were performed.
Common laboratory methods
Liquid chromatography
Commonly used to measure cannabinoid content. It separates individual cannabinoids so acidic and neutral forms can be measured independently.
Gas chromatography
Commonly used for volatile compounds, including residual solvents and some aroma compounds. It may also be used for certain cannabinoid analyses.
Liquid chromatography with mass spectrometry
A sensitive method often used to detect very small amounts of compounds such as pesticides and mycotoxins.
Elemental analysis
Commonly used for heavy metal testing and capable of measuring very small amounts of metals such as lead, cadmium, arsenic and mercury.