Cannabis test labs and ISO 17025 accreditation

Posted April 17, 2019

Around the world, ISO—the International Organization for Standardization—is synonymous with standards, and that’s just what the cannabis industry needs. In analytical labs, ISO is like the Good Housekeeping Seal of approval. It means that someone with authority endorses what a lab is doing and, how it does it. Although ISO has published 21,613 International Standards, the most common one sought by cannabis analytical labs is ISO/IEC 17025. According to ISO, this standard “specifies the general requirements for the competence to carry out tests and/or calibrations, including sampling.”

Adequate safety testing for Cannabis is an attainable goal. Many of the existing Cannabis testing laboratories are now well-staffed and well-funded. Competent laboratories will have little difficulty meeting the accreditation criteria used by both the private sector and the governmental regulatory bodies that oversee the laboratories that test our food, soil, medicines, and drinking water. These criteria are consolidated in the International Organization for Standardization (ISO) guidelines known as ISO 17025 (General requirements for the competence of testing and calibration laboratories), and they are clear, effective, and universally accepted.

The testing of Cannabis must be performed by laboratories that have been able to demonstrate their competence through well-established accreditation mechanisms. Accreditation is a formal recognition by an authoritative third-party of a laboratory’s competence to perform specific tests. This accreditation infrastructure is well established by the mutual recognition arrangement (MRA) among accreditation bodies through the International Laboratory Accreditation Cooperation (ILAC). ILAC functions as a forum for harmonizing laboratory and inspection body accreditation procedures and policies, thus promoting accreditation as a mechanism to enhance confidence in testing and inspection facilities.

Multiple resources are also available to assist laboratories in preparing for accreditation. ISO 17025 consultants can be hired to perform a gap analysis on their quality system and various training courses are offered by Accreditation Bodies on the basics of accreditation, internal auditing, root cause analysis, etc.

Scope of Accreditation

ISO 17025 does not specify what methods a laboratory uses. Laboratories must themselves define the methods included within their scope of accreditation. In order for a Cannabis testing laboratory to be fully accredited across all of its relevant methodologies, its scope must include identification and quantitation of those components and potential contaminants relevant to public health. These will fall into the following categories.

  1. Pesticides. These should be tested for using methods based on AOAC Official Method 2007.01 (or on more effective methods when they become available) with a state-mandated subset of the chemicals specified therein. The Cannabis Safety Institute white paper on pesticides will specify a list that laboratories should be required to test for.
  2. Cannabinoids, including, at a minimum, THC, THCA, CBD, and CBDA. This must include extraction methods for dealing with the variety of matrices found in edible products.
  3. Microbiology testing: detection and quantitation of all relevant bacterial and fungal species specified in state guidelines.
  4. Volatile Organic Compounds (VOCs), often referred to as residual solvent testing (for extracts made with hydrocarbon or organic solvents).
  5. Water Activity (a measure of water available to support microbial growth; not substitutable by moisture content measurements).

Most established Cannabis laboratories also test for plant compounds known as terpenes. These are not considered harmful, but in view of their increasing importance and the increasing evidence that they contribute significantly to the characteristics of each Cannabis variety, laboratories should be expected to add these tests to their scope. Cannabis testing laboratories should, of course, also include in their scope any other assay required under state law.


Third-party laboratory accreditation can help to demonstrate that a lab is structured properly, that it has adequate documentation of all of its procedures and quality assurance methods, and that it follows these procedures and methods. Additionally the laboratory must ensure is that it has its test methods in control. One means to achieve this is through the use of proficiency testing using blinded samples provided for analysis. All ISO 17025 accredited laboratories must participate in proficiency testing activities when they are relevant and available.

Accreditation to the internationally accepted ISO 17025 standard for testing laboratories, in combination with a rigorous proficiency testing program, is the proven approach for ensuring the quality and reliability of the vast majority of analytical cannabis laboratories. Paradigm 3 is a compliance management software that manages various facets of your ISO 17025 system such as document control, corrective action, training and competency and calibration.