A cannabis lab report, also called a certificate of analysis (COA), shows potency and contaminant results for one batch of product. A licensed lab runs the tests. State agencies set the pass or fail limits.
Cannabis Product Lab Test Certificate: How to Read a COA
What a lab report contains
Each COA covers one batch. Reports list a batch or lot number, a harvest date, a test date, and the lab license number. Six test groups appear on most reports:
- Cannabinoid potency
- Terpenes
- Pesticides
- Heavy metals
- Microbials and mycotoxins
- Residual solvents
Cannabinoid potency and total THC
Potency is a percent of sample weight. Raw flower holds THC in acid form, THCA. Heat removes the acid group and converts THCA to THC. Labs report both numbers.
Total THC uses a conversion factor: Total THC = (THCA × 0.877) + delta-9 THC. The 0.877 figure accounts for the mass lost when the acid group leaves the molecule. Total CBD uses the same math with CBDA.
what does lab tested cannabis mean
Example: flower with 20% THCA and 0.5% THC reads as 18.04% total THC.
Contaminant tests and action limits
A result below the action limit is a pass. A result at or above the limit is a fail, and the batch cannot be sold.
Pesticide panels cover dozens of compounds. Heavy metal tests cover lead, cadmium, arsenic, and mercury. Microbial tests count total yeast and mold in colony forming units per gram (CFU/g). Mycotoxin tests cover aflatoxin and ochratoxin A. Residual solvent tests measure parts per million (ppm) left over from extraction.
Limits differ by state and by product type. Edible limits are often stricter than flower limits.
How to read the numbers
"ND" means not detected. "LOQ" means limit of quantitation, the lowest level the instrument can measure. A result below the LOQ prints as ND or "<LOQ."
Terpenes print as a percent for flower and as ppm for concentrates. Common terpenes: myrcene, limonene, pinene, linalool, and caryophyllene.
Flower reports also show moisture content and water activity. Water activity above 0.65 supports mold growth.
What a report does not tell you
A COA covers one sample from one batch. It does not show storage conditions after the test. It does not list dose, onset time, or effects. Potency numbers shift with the test method, so compare results from the same lab.
Match the batch number on the package to the number on the report.