Cannabis distributors are responsible for ensuring the safety, consistency, and compliance of products before they reach consumers. To achieve this, distributors rely extensively on accredited laboratories and rigorous quality-control protocols. Below are the key steps in the lab testing and quality-control process—and why each is essential.

1. Sampling and Chain of Custody

Before testing, distributors collect representative samples of each lot—flowers, edibles, concentrates, or topicals—following state-mandated sampling protocols. These may include random sampling of a defined percentage of the product lot or third-party collection to prevent tampering. Each sample is logged, sealed, and tracked through a secure chain of custody to maintain integrity and regulatory compliance.

2. Submission to Accredited Labs

Samples are then submitted to licensed, third-party laboratories accredited under ISO/IEC 17025 or equivalent state standards. Accreditation ensures labs follow best practices—such as validated methods, proficiency testing, and strict quality systems like Good Laboratory Practices.

3. Analytical Testing

Labs analyze samples for:

• Potency: Measuring THC, CBD, and other cannabinoids. Results must be reported on a dry-weight basis.
• Contaminants: Screening for pesticides, heavy metals, residual solvents, mycotoxins, and microbial contaminants (mold, bacteria, yeast). These tests prevent health risks such as respiratory illness or poisoning.
• Homogeneity: Especially for edibles and infused products, ensuring consistent dosing per serving, which is crucial for consumer safety.

Throughout testing, quality-control measures are in place. Labs use instrument calibration, method blanks, replicates, and standards to monitor accuracy. They also retain specimens and follow corrective-action procedures if tests fail or produce unexpected results.

4. Certificate of Analysis (COA)

When tests pass, labs issue a Certificate of Analysis (COA)—a formal report detailing results, testing methods, detection limits, and pass/fail status. The COA is a key compliance document. Distributors and retailers must keep COAs on file for audits and often make them available to consumers. COAs also allow regulators to track each product and verify safety data before distribution into retail channels.

5. Handling Failures and Retesting

If a sample fails testing due to pesticide residue, microbial contamination, or labeling errors, distributors must halt further processing. They must quarantine the affected batch, then decide to either destroy the product or attempt remediation under approved methods. If they remediate the product—for example, by sterilizing mold-infested flower—it must be retested by an accredited lab before it can enter commerce.

6. Internal QA/QC and Audit Readiness

Beyond lab testing, most distributors maintain an internal Quality Assurance program. Staff review batch records and laboratory data to ensure accuracy, and they often conduct their own audits of suppliers. Quality assurance teams verify the integrity of the chain of custody, adherence to testing requirements, proper labeling, and that all batches are traceable in state-mandated inventory control systems.

Preparing for audits by state regulators is critical. Thorough recordkeeping, ongoing staff training, and periodic supplier and lab reviews help prevent enforcement actions, recalls, or license suspension.

Why This Matters

1. Protects consumer health: Detecting mold, pesticides, and other contaminants prevents serious illnesses.
2. Ensures dosage consistency: Accurate cannabinoid content prevents under- or overdosing and protects consumers’ well-being.
3. Meets legal requirements: Every legal state requires testing, COAs, and traceable distribution; noncompliance can lead to recalls, fines, or license revocation.
4. Preserves brand reputation: Rigid quality-control protocols build trust with consumers and avoid legal and business risks, ensuring long-term success.