COAs and testing
What is a COA (certificate of analysis)?
Written by: Author pendingReviewed by: Reviewer pendingUpdated:
A certificate of analysis is a lab report for one production batch that states measured cannabinoid content, THC and THCa, and contaminant results. Independent labs accredited to ISO/IEC 17025:2017 issue them (A2LA). Carriers and states rely on them: USPS requires mailers to keep lab results for at least 3 years.
A certificate of analysis, or COA, is the document that turns a label claim into a measurement. The label says 1,500 mg CBD; the COA says what a laboratory actually found in that batch. For hemp products, the COA is also the paper trail that carriers, states and wholesale buyers ask for. Every batch sold here links to its own report on the product page and at /lab-results.
What is on a COA?
A complete hemp COA has four parts:
- Identity. Product name, batch or lot number, sample received date, test date, and the name and accreditation of the laboratory. The batch number must match the one printed on the bottle in your hand.
- Cannabinoid potency. Measured amounts of CBD, CBDa, CBG, CBN, delta-9 THC, THCa and others, reported as a percentage by weight and as milligrams per unit (per mL, per gummy, per container). A total THC line should apply USDA's formula, Total THC = (0.877 x THCA) + THC (7 CFR 990.1).
- Contaminants. Pesticides, heavy metals, residual solvents, microbial contaminants and mycotoxins, each with a pass or fail against an action level. See What contaminants are hemp products tested for?.
- Method notes. The instrument used, the limit of quantitation (LOQ) for each analyte, and often the measurement uncertainty. "ND" means below that LOQ, not zero; the arithmetic is at What does ND mean on a COA?.
Why do COAs matter for CBD specifically?
Because labels have a poor track record. A 2017 JAMA study bought 84 CBD extracts from 31 companies online and found only 30.95 percent were labeled within 10 percent of their measured CBD content; 42.85 percent contained more than labeled and 26.19 percent contained less. THC was detected, up to 6.43 mg/mL, in 18 of the 84 samples (JAMA 2017). A batch-specific COA from an independent lab is the only way a buyer can check the number on the front of the bottle.
Who requires a COA?
- Carriers. USPS Publication 52 permits compliant hemp products in domestic mail only when the mailer keeps records such as lab results and licenses "for no less than 3 years after the date of mailing" (USPS Pub 52). UPS states that effective December 11, 2026, raw hemp shipments must contain a certificate of analysis showing total THC including THCa of not more than 0.3 percent (UPS).
- States. Oregon's Hemp Registry, in force since January 1, 2026 with enforcement from June 1, 2026, requires that test results be made accessible to consumers for every cannabinoid hemp product sold in the state (OLCC).
- Wholesale buyers. Retail accounts and distributors ask for the COA before they list a product, and many state retailer licenses require them on file.
Who issues a credible COA?
An independent laboratory accredited to ISO/IEC 17025:2017, the international standard for testing and calibration laboratories. ISO describes the standard's purpose as enabling laboratories to demonstrate that they "operate competently and generate valid results" (ISO). A2LA, one of the U.S. accreditation bodies, assesses cannabis and hemp testing laboratories to that standard and layers on state-specific requirements where a state has signed a memorandum with the accreditor (A2LA). More on what accreditation does and does not prove is at What is ISO/IEC 17025 accreditation?.
An in-house report from the manufacturer's own bench is not a COA in this sense. Look for the accreditation body's mark, the certificate number, and a lab name you can verify on the accreditor's directory.
General information, not personalized guidance.
Sources
- Cannabis Testing Laboratory Accreditation A2LA (accessed 2026-10-13)
- ISO/IEC 17025, Testing and calibration laboratories International Organization for Standardization (accessed 2026-10-13)
- Publication 52, 453.37 Hemp and Hemp-based Products United States Postal Service (accessed 2026-10-13)
- Shipping Hemp and Hemp-Derivatives UPS (accessed 2026-10-13)
- Labeling Accuracy of Cannabidiol Extracts Sold Online JAMA, via PubMed Central (accessed 2026-10-13)
- OLCC Announces Hemp Registry, Bringing Transparency to the Market Oregon Liquor and Cannabis Commission (accessed 2026-10-13)
- 7 CFR 990.1, Definitions Cornell Law School, Legal Information Institute (accessed 2026-10-13)
Related questions
How do I read a CBD lab report?
Match the batch number to your bottle, then read four things: measured CBD per mL or per piece versus the label, total THC using USDA's formula of 0.877 x THCa plus delta-9 (7...
What does ND mean on a COA, and what is LOQ?
ND means "not detected" above the lab's limit of quantitation (LOQ), the smallest amount the method can measure reliably. It is not zero. With a 0.01 percent LOQ, a 30 mL bottle...
What is ISO/IEC 17025 accreditation and why does it matter?
ISO/IEC 17025:2017 is the international standard for the competence of testing and calibration laboratories. Accreditation means an independent body has assessed the lab against...
What contaminants are hemp products tested for?
A full hemp panel covers five contaminant classes: pesticides, heavy metals, residual solvents, microbial contaminants and mycotoxins, plus water activity and moisture for...