Every legal cannabis product in Canada has been tested by a licensed laboratory before reaching the shelf. These test results—compiled in Certificates of Analysis (COAs)—contain valuable information about what you're consuming. The problem? Most people don't know how to read them.
This guide breaks down everything on a cannabis lab report: what those numbers mean, what to look for, and how to use this information to make better purchasing decisions.
What Is a Certificate of Analysis (COA)?
A COA is an official document from a licensed testing laboratory that verifies the contents of a cannabis product. Think of it as a detailed ingredient and quality report that answers three key questions:
- How potent is it? (Cannabinoid content)
- What's the flavour/effect profile? (Terpene content)
- Is it safe? (Contaminant testing)
Deep dive into COA structure →
Cannabinoid Content: Understanding Potency
The cannabinoid section is what most people look at first—and for good reason. But there's more nuance here than just "bigger number = stronger."
THC vs THCA vs Total THC
This is where many people get confused. Here's the breakdown:
- THCA (Tetrahydrocannabinolic Acid): The raw, non-psychoactive form found in fresh cannabis. It doesn't produce a high on its own.
- THC (Delta-9-THC): The active, psychoactive form that produces effects.
- Total THC: What you'll actually experience when you consume the product.
The Conversion Formula
When you heat cannabis (smoking, vaping, baking), THCA converts to THC. But THCA is heavier than THC, so the conversion isn't 1:1:
Total THC = (THCA × 0.877) + THC
The 0.877 factor accounts for the weight lost when THCA loses its carboxyl group during decarboxylation (heating).
Example: A flower with 25% THCA and 0.5% THC has:
Total THC = (25 × 0.877) + 0.5 = 22.4%
Learn more about THC calculations →
What THC Percentages Mean
| Total THC | Potency Level | Best For |
|---|---|---|
| Under 10% | Low/Mild | Beginners, microdosing, daytime use |
| 10-15% | Moderate | Occasional users, balanced experience |
| 15-20% | Strong | Regular consumers |
| 20-25% | Very Strong | Experienced users |
| 25%+ | Extremely Strong | High tolerance consumers |
Complete THC percentage guide →
The THC Percentage Myth
Here's something many consumers don't realize: higher THC doesn't always mean a better experience.
Research and anecdotal evidence increasingly suggest that terpene profiles and the overall cannabinoid/terpene combination matter more than raw THC numbers. A 20% THC strain with a terpene profile that suits your needs may provide a more enjoyable experience than a 28% THC strain that doesn't.
Think of it like alcohol: a craft beer at 6% ABV can be more enjoyable than cheap vodka at 40% ABV. Potency isn't everything.
Why THC percentage isn't everything →
CBD Content
CBD (Cannabidiol) is the other major cannabinoid to understand:
- High THC, Low/No CBD: Full psychoactive experience
- Balanced (1:1 or similar): Moderate effects, often described as more manageable
- High CBD, Low THC: Minimal psychoactive effects
Some research suggests CBD may moderate some of THC's effects, potentially reducing anxiety for some people. Balanced products are popular among those who find high-THC products too intense.
Minor Cannabinoids
Some COAs list additional cannabinoids:
- CBN (Cannabinol): Forms as THC ages. Associated with sedation.
- CBG (Cannabigerol): Non-psychoactive, sometimes called the "mother cannabinoid."
- THCV (Tetrahydrocannabivarin): May produce shorter, more energetic effects.
- CBC (Cannabichromene): Non-psychoactive, being researched for various properties.
Learn about minor cannabinoids →
Terpene Content: Flavour and Effect Profiles
Not all COAs include terpene testing, but when they do, this section is gold. Terpenes may be the best predictor of how a strain will actually feel.
Reading Terpene Results
Total Terpene Content:
- Under 1%: Low terpene content, milder aroma
- 1-2%: Moderate, noticeable aroma
- 2%+: High terpene content, pronounced aroma and flavour
Individual Terpenes: Usually listed by percentage. The top 2-3 terpenes typically define the strain's character.
Common Terpenes and Their Associations
- Myrcene: Earthy, relaxing
- Limonene: Citrus, uplifting
- Pinene: Pine, alert
- Linalool: Floral, calming
- Caryophyllene: Spicy, grounding
Safety Testing: What "Pass" Means
This section verifies the product is safe to consume. All results should show "Pass," "ND" (Not Detected), or be below acceptable limits.
Microbial Testing
Screens for harmful microorganisms:
- Total Yeast and Mold: Must be below threshold
- E. coli: Must not be detected
- Salmonella: Must not be detected
- Aspergillus: Dangerous mold species, must not be detected
Cannabis mold testing explained →
Pesticide Testing
Screens for residues from cultivation. Legal cannabis must be grown without prohibited pesticides, and any residues must be below Health Canada's strict limits.
Heavy Metals Testing
Cannabis plants can absorb heavy metals from soil. Testing screens for:
- Lead
- Arsenic
- Mercury
- Cadmium
All must be below acceptable limits.
Heavy metals testing explained →
Residual Solvents (Extracts Only)
For concentrates and extracts made with solvents, testing ensures extraction chemicals have been properly purged:
- Butane
- Propane
- Ethanol
- Other solvents used in extraction
Results should show these are below safe thresholds or not detected.
Other Information on COAs
Batch/Lot Number
Identifies the specific production batch. Useful if you find a product you love and want to find the same batch again.
Test Date
When the testing was performed. More recent tests reflect current product quality more accurately.
Package Date
When the product was packaged. For flower, fresher is generally better for terpene preservation. Look for products packaged within the last 3-6 months for optimal freshness.
How to Use Lab Results
Finding COAs
- QR codes: Many packages have scannable codes linking to test results
- Producer websites: Often have COAs searchable by lot number
- Ask your budtender: We can help you find and interpret results
Making Decisions
- Start with safety: Verify all safety tests passed
- Check Total THC: Match potency to your tolerance and desired intensity
- Review terpenes: If available, look for terpene profiles that match your desired experience
- Consider freshness: Check package date, especially for flower
- Note the batch: If you find something you love, record the lot number
Red Flags to Watch For
- Missing or expired COA: All legal products should have current testing
- Failed safety tests: Never consume products with failed contaminant tests
- Mismatched numbers: If package claims don't match COA, something's wrong
- Very old package dates: Terpenes degrade over time; old flower may be less flavourful
Lab Results for Different Products
Flower
Focus on: Total THC, terpene profile, package date (freshness)
Pre-Rolls
Same as flower. Note that pre-ground cannabis may show slightly lower terpene content.
Vape Cartridges
Focus on: Cannabinoid content, whether terpenes are cannabis-derived (CDT) or botanical, residual solvent testing
Edibles
Focus on: THC per serving, THC per package, accurate labelling. Terpene content is less relevant as most are lost in processing.
Concentrates
Focus on: Cannabinoid percentages (often 60-90%+ THC), terpene content (especially for live products), residual solvent testing
Concentrates guide →
Get Help Reading Lab Results at Smokey's
Lab results can feel overwhelming at first, but they're a powerful tool for finding products you'll consistently enjoy. Our budtenders are trained to help you interpret COAs and find products that match what you're looking for.
Bring in a COA you're curious about, or ask us to walk you through the test results for any product in our store. We're always happy to help you become a more informed consumer.