COAs and testing
What is ISO/IEC 17025 accreditation and why does it matter?
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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 it, so results can be trusted across borders (ISO). U.S. accreditors such as A2LA assess cannabis and hemp labs to the 2017 edition.
"ISO 17025 accredited" appears on nearly every hemp lab report. It is worth knowing what the phrase does and does not promise, because it is the main quality signal a buyer has when choosing between two COAs.
What is ISO/IEC 17025?
ISO/IEC 17025 is the international standard titled "General requirements for the competence of testing and calibration laboratories." ISO describes its purpose directly: the standard "enables laboratories to demonstrate that they operate competently and generate valid results," which in turn lets test reports be accepted between countries without retesting (ISO). The current edition is ISO/IEC 17025:2017; the prior version dated from 2005, and ISO notes the 2017 revision added technical updates, new vocabulary, IT developments, and an element of risk assessment.
The standard applies to any organization that performs testing, sampling or calibration, whether government, industry or academic. A hemp potency lab, a pesticide residue lab and an aerospace materials lab can all be accredited to the same document.
What does accreditation actually assess?
Accreditation is a third-party audit against the standard by a recognized accreditation body. In the United States the main bodies for cannabis and hemp testing include A2LA, which states that "Cannabis and hemp testing laboratories are assessed and accredited to ISO/IEC 17025:2017" and that state-specific requirements are assessed when incorporated into the lab's quality management system or required by a memorandum of understanding with the state (A2LA).
The assessment covers both management and technical competence: staff qualifications, method validation, equipment calibration, measurement uncertainty, proficiency testing, sample handling, record keeping and impartiality. A2LA describes the standard as "non-prescriptive and flexible," meaning it specifies what a lab must demonstrate, not which instrument it must buy (A2LA).
Measurement uncertainty is a good example of why that matters. USDA's hemp rule defines acceptable hemp THC level by applying the lab's measurement of uncertainty to the reported total THC and asking whether the resulting range includes 0.3 percent (7 CFR 990.1). A lab that cannot state its uncertainty cannot produce a compliant crop test.
Why does it matter for hemp specifically?
Three reasons.
- Regulators are starting to require it. New Jersey's intoxicating hemp beverage rules require testing by an accredited laboratory (NJ CRC). State cannabis programs generally license only accredited labs, and hemp rules are converging on the same expectation.
- The market has a history of inaccurate labels. A 2017 JAMA study of 84 CBD extracts bought online found only 30.95 percent labeled within 10 percent of measured content (JAMA 2017). An accredited lab's report is the check on that.
- Compliance now turns on small numbers. From December 11, 2026, the federal hemp definition caps final products at 0.4 mg total THC per container. Proving that requires an ND result at a low LOQ from a method the lab has validated, which is exactly what accreditation audits. See What does ND mean on a COA, and what is LOQ?.
What does accreditation not prove?
It does not prove a specific result is right; it proves the lab has a system that should produce right results and is checked by outsiders. It does not cover tests outside the lab's accredited scope, so check that the scope includes cannabinoid potency in the relevant matrix and the contaminant panels listed on the COA. It does not stop a brand from sending a cherry-picked sample, which is why batch numbers and sampling notes matter.
How do I verify a lab's accreditation?
Take the accreditation certificate number from the COA and look it up on the accreditor's public directory (A2LA, ANAB and others publish searchable lists). Confirm the scope lists cannabis or hemp testing and the specific methods. If the report shows no accreditor or no certificate number, ask the brand for a report from a lab that has one. Reports linked from this site name the laboratory and its accreditor on every page.
General information, not personalized guidance.
Sources
- ISO/IEC 17025, Testing and calibration laboratories International Organization for Standardization (accessed 2026-10-13)
- Cannabis Testing Laboratory Accreditation A2LA (accessed 2026-10-13)
- 7 CFR 990.1, Definitions Cornell Law School, Legal Information Institute (accessed 2026-10-13)
- Intoxicating Hemp FAQs New Jersey Cannabis Regulatory Commission (accessed 2026-10-13)
- Labeling Accuracy of Cannabidiol Extracts Sold Online JAMA, via PubMed Central (accessed 2026-10-13)
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