1. Collecting and Preparing Cannabis Samples

Laboratories begin the testing process by collecting regulated, representative samples, which ensures that every product—from flower to edibles—undergoes accurate assessment. Technical standards require labs to test samples for potency, homogeneity, stability, and contaminants under strict chain‑of‑custody rules.

Next, technicians prepare samples using standardized workflows:

• Dry, grind, and homogenize plant material to create uniform test portions.
• Measure moisture content and mass to maintain consistency during extraction, using validated prep tools that reduce variability.
• Perform solvent extractions (e.g., methanol or acetonitrile) to isolate cannabinoids and contaminants.
• Use syringe or membrane filtration, an important step that directly affects cannabinoid recovery before potency analysis.

2. Measuring Potency Through Cannabinoid Quantification

Cannabis potency testing determines the levels of major cannabinoids—including THC, THCA, CBD, CBDA, CBG, and CBN—so that consumers receive correct dosing information. Because potency inflation has become a widespread issue, laboratories must perform highly accurate cannabinoid quantification.

To achieve precise measurements, labs rely on advanced analytical instruments:

• High‑Performance Liquid Chromatography (HPLC) quantifies acidic and neutral cannabinoids without thermal degradation.
• Liquid Chromatography–Tandem Mass Spectrometry (LC‑MS/MS) identifies minor cannabinoids and complex isomers with high sensitivity, especially in semi‑synthetic cannabinoid products.

Additionally, edibles and beverages undergo homogeneity testing, which determines whether cannabinoids are distributed consistently throughout the product.

3. Screening for Contaminants to Protect Consumer Safety

After potency testing, laboratories shift their focus to comprehensive contaminant screening, a crucial part of safeguarding public health. Cannabis can accumulate or retain contaminants such as pesticides, heavy metals, solvents, microbes, and chemical byproducts.

A. Pesticides and Heavy Metals

Labs use Liquid Chromatography-Tandem Mass Spectrometry (LC‑MS/MS) to identify pesticide residues and Inductively Coupled Plasma Mass Spectrometry (ICP‑MS) to measure heavy metals like lead or arsenic—substances that pose significant toxicity risks even at low levels.

B. Residual Solvents

Because extraction methods may leave chemical traces, laboratories use Gas Chromatography (GC) to detect solvents such as butane, propane, and ethanol.

C. Microbiological Contaminants and Mycotoxins

To prevent exposure to harmful mold, yeast, bacteria, and aflatoxins, labs apply ELISA assays and liquid chromatography‑based toxin detection. These methods identify microbial dangers linked to respiratory illness and foodborne infections.

D. Byproducts in Semi‑Synthetic Cannabinoids

Because the rise of chemically altered hemp products introduces unknown byproducts, labs test for unintended reaction residues and isomers that form during conversion processes. These impurities often go undetected without high‑resolution analytical methods, highlighting the importance of specialized safety testing.

E. Stability and Foreign Material Testing

Regulators also require labs to evaluate a product’s stability—determining expiration dates—and test for foreign material, ensuring that no contaminants such as fibers or plastics enter the supply chain.

4. Maintaining Laboratory Accreditation and Quality Assurance

To ensure reliability, cannabis laboratories follow ISO/IEC 17025 accreditation standards, which confirm competence in analytical testing and data quality. Labs must validate all methods, follow calibration standards, and maintain rigorous documentation systems.

Furthermore, organizations like AFDO maintain national directories of regulatory guidance, accreditation programs, and proficiency testing resources, supporting uniform testing quality across the U.S.

5. Reporting Results Through Certificates of Analysis 

After completing all analytical steps, laboratories issue a Certificate of Analysis (COA), which documents:

• cannabinoid potency values,
• pass/fail results for contaminant screenings,
• detailed testing methods and detection limits,
• regulatory thresholds and batch identification numbers.

Because packaging claims cannot always be trusted, COAs serve as the only reliable verification of product potency, safety, and compliance.

Recent industry findings emphasize that consumers should rely exclusively on independently issued COAs to avoid mislabeling and unsafe products.

Finally, states require labs to upload results into digital compliance systems, creating transparency from cultivation to retail.