ISO/IEC 17025

ISO/IEC 17025 is the international standard specifying the competence, impartiality and consistent operation required of testing and calibration laboratories.

Accreditation to it means an independent accrediting body has audited the laboratory's methods, equipment, staff qualifications, quality system and proficiency testing, and continues to reassess it periodically. Each accreditation has a defined scope listing the specific tests covered, so a laboratory may be accredited for cannabinoid potency but not for pesticides, or the reverse.

For a reader of a certificate of analysis, accreditation is the most meaningful single indicator that results were produced under an external standard rather than self-declared good practice. The accrediting body's name and the certificate number often appear on the report, and scopes can be checked on the accrediting body's website. Accreditation does not guarantee that any particular result is correct, and it says nothing about the product's effects, but it makes systematic error less likely and gives the results standing.