How to Read a Cannabis Certificate of Analysis (COA)
A COA is the most important document in cannabis compliance. It proves your product has been tested and meets state requirements. Here is how to read one.
What is a COA?
A Certificate of Analysis (COA) is an official document from a licensed testing laboratory that reports the results of tests performed on a cannabis sample. Every legal cannabis product sold in the US must have a COA from a state-licensed lab.
The COA confirms that the product meets state-mandated safety thresholds for contaminants and accurately reports cannabinoid and terpene content. Without a valid COA, a cannabis product cannot legally be sold.
Key Sections of a COA
1. Sample Information
The top of every COA identifies the sample. Look for the batch number, sample ID, date received, date tested, and the name of the product or strain. This section should match the product label exactly. Any discrepancy is a red flag.
2. Cannabinoid Profile (Potency)
This section shows THC, CBD, and other cannabinoid concentrations. Results are typically shown in both percentage (%) and milligrams per gram (mg/g). Key values to look for:
- Total THC - calculated as THCA x 0.877 + delta-9 THC. This is what determines the psychoactive potency.
- Total CBD - calculated as CBDA x 0.877 + CBD.
- Minor cannabinoids - CBG, CBN, CBC, and others may be listed depending on the lab.
3. Terpene Profile
Terpenes are aromatic compounds that contribute to the flavor, smell, and effects of cannabis. Common terpenes include myrcene, limonene, pinene, linalool, and caryophyllene. Not all states require terpene testing, but it is valuable information for quality assessment.
4. Pesticide Screening
This section tests for residual pesticides. Results will show either "pass" or "fail" against state action limits, or list specific pesticide concentrations in parts per billion (ppb). Any detection above the state limit means the product fails and cannot be sold.
5. Heavy Metals
Cannabis plants can absorb heavy metals from soil. Labs test for four primary heavy metals: lead, arsenic, cadmium, and mercury. Results are measured in parts per million (ppm) or micrograms per gram (ug/g).
6. Microbial Screening
Tests for harmful microorganisms including E. coli, Salmonella, Aspergillus, and total yeast and mold counts (TYMC). This is particularly important for immunocompromised patients using medical cannabis.
7. Residual Solvents
For extracts and concentrates, this section tests for leftover solvents used in extraction (butane, propane, ethanol, etc.). Flower products typically skip this test. Results are measured in ppm.
8. Moisture Content and Water Activity
High moisture content promotes mold growth. Water activity (Aw) above 0.65 is a risk factor. These tests help ensure product stability and shelf life.
Red Flags to Watch For
- Missing lab accreditation - the lab should list ISO/IEC 17025 accreditation or state-specific certification
- No batch/sample ID - every COA must be traceable to a specific batch
- Unusually high THC - potency above 35% for flower should be scrutinized (possible inflated results from lab shopping)
- Missing test categories - if a required test is absent, the COA is incomplete
- Expired dates - COAs are typically valid for 12 months from the test date
Finding a Trusted Lab
The quality of a COA depends entirely on the lab that produced it. Use our testing lab directory to find ISO 17025 accredited labs in your state, compare turnaround times, and verify licensing.
Frequently Asked Questions
What is a COA in cannabis?
A Certificate of Analysis (COA) is an official document from a licensed testing laboratory that reports the results of tests performed on a cannabis sample. It confirms the product meets state safety thresholds and accurately reports cannabinoid content.
How do I verify a cannabis COA is real?
Check that the COA includes the lab's name and accreditation number, a unique batch/sample ID, the date tested, and that the lab is listed on your state's regulatory agency website.
What should I look for on a cannabis COA?
Key sections include cannabinoid potency (THC/CBD percentages), terpene profile, pesticide screening results, heavy metal levels, microbial contaminant testing, and residual solvent results.
How long is a cannabis COA valid?
Cannabis COAs are typically valid for 12 months from the test date. After that, the product should be retested.
What does it mean if a cannabis product fails testing?
A failed test means the product exceeded allowable contaminant limits. Failed products cannot be sold until remediated and retested, or they must be destroyed.
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