Legal cannabis products undergo laboratory testing to verify potency and safety. Understanding how to read cannabis lab results helps you make informed purchasing decisions and ensure product quality.
What Is a COA?
A Certificate of Analysis (COA) is a document from an accredited laboratory that details the chemical composition and safety of a cannabis product. Most legal markets require COAs for all products sold.
Key Components of Cannabis Lab Testing
Potency Testing
Measures cannabinoid content, primarily THC and CBD, but may include CBN, CBG, THCA, CBDA, and other cannabinoids.
Understanding THC Percentages
- Total THC = THCA × 0.877 + THC
- THCA converts to THC when heated
- Raw flower shows mostly THCA
- Activated products show THC
What the Numbers Mean
- 10-15% THC: Mild potency
- 15-20% THC: Moderate potency
- 20-25% THC: Strong potency
- 25%+ THC: Very high potency
Terpene Analysis
Shows the terpene profile and percentages. Higher terpene content (2-4%+) generally indicates better quality and more pronounced effects.
Contaminant Testing
Pesticides
Tests for harmful pesticide residues. Results should show "ND" (not detected) or below action limits.
Heavy Metals
Screens for lead, arsenic, cadmium, and mercury. Should be below safety thresholds.
Microbials
Tests for mold, bacteria, and other pathogens. Critical for immunocompromised patients.
Residual Solvents
Important for concentrates. Ensures extraction solvents were properly removed.
Mycotoxins
Toxins produced by mold. Should not be detected.
How to Read a COA
Check the Basics
- Product name matches what you're buying
- Batch/lot number matches packaging
- Test date is recent
- Laboratory is accredited
Review Potency
- Total THC and CBD percentages
- For edibles: mg per serving and per package
- Compare to label claims
Check Safety Tests
- All contaminants should pass
- "ND" or "Not Detected" is ideal
- Any failures should disqualify the product
Red Flags to Watch For
- Missing or outdated COA
- Lab not accredited
- Batch numbers don't match
- Failed contaminant tests
- THC levels significantly different from label
- No terpene data (indicates lower quality testing)
Why Lab Testing Matters
Untested cannabis may contain harmful pesticides, heavy metals from soil, mold and bacteria, inaccurate potency leading to overconsumption, and residual solvents in concentrates.
Always purchase from licensed dispensaries that provide lab-tested products. Find licensed dispensaries near you.