Every legal cannabis product in California gets tested by a licensed lab. The results show up on a document called a Certificate of Analysis, or COA for short.
Most people ignore these lab results. The numbers and abbreviations look confusing. But learning to read a COA only takes a few minutes. Once you understand the basics, you can make smarter buying decisions and know exactly what you’re putting in your body.
This guide breaks down each section of a cannabis lab test in plain language.
What Is a COA?
A Certificate of Analysis is an official report from a third-party testing lab. California requires all cannabis products to pass lab testing before they can be sold legally.
The COA tells you what’s actually in the product. It shows cannabinoid levels, terpene content, and whether the product passed safety tests for things like pesticides and mold.
You can usually find COA information on the product packaging, the dispensary’s website, or by scanning a QR code on the label. Some budtenders can also pull up lab results if you ask.
Why Lab Tests Matter
Without lab testing, you have no way to verify what’s in a cannabis product. The THC percentage on the label might be wrong. The product might contain harmful chemicals. You’d have no way to know.
Lab tests protect you by confirming:
- The product contains what the label claims
- Cannabinoid percentages are accurate
- No dangerous levels of pesticides, heavy metals, or mold are present
- The product is safe to consume
This is one of the biggest advantages of buying from licensed dispensaries. You get verified, tested products instead of mystery bags.
The Main Sections of a COA
Most COAs follow a similar format. Let’s walk through each section.
Product Information
At the top, you’ll see basic details about the product:
- Product name and type (flower, cartridge, edible, etc.)
- Batch or lot number
- Sample date and test date
- The name of the testing lab
- License numbers for the producer and lab
This information helps you verify you’re looking at the right test for your specific product. Batch numbers should match what’s printed on your packaging.
Cannabinoid Profile
This section shows how much of each cannabinoid is in the product. The main ones you’ll see are:
THC (Delta-9 THC): The compound that produces the high. Listed as a percentage for flower and concentrates, or in milligrams for edibles.
THCA: The raw, non-active form of THC found in unheated cannabis. When you smoke or vape, heat converts THCA into THC. Most of the “THC” in flower is actually THCA until you apply heat.
Total THC: This number estimates the total THC you’ll get after THCA converts. The formula is: Total THC = THC + (THCA x 0.877). This is often the most useful number to look at for flower.
CBD: The non-intoxicating cannabinoid associated with relaxation and relief. Some products have significant CBD, while many recreational products have very little.
CBDA: The raw form of CBD, similar to how THCA relates to THC.
Total CBD: The estimated CBD after conversion, calculated the same way as Total THC.
CBN: A cannabinoid that forms as THC ages. Higher CBN can indicate older product. CBN is associated with sedating effects.
CBG: A minor cannabinoid some users seek out for specific effects.
You might see other cannabinoids listed too. For most people, Total THC and Total CBD are the numbers that matter most.
How to Interpret Cannabinoid Numbers
For flower, cannabinoids are listed as percentages. A flower with 25% Total THC means that for every gram, about 250 milligrams will be THC when heated.
For edibles, cannabinoids are listed in milligrams per serving and per package. A gummy might say “10mg THC per piece” with “100mg THC per package” if there are 10 gummies.
For concentrates and cartridges, you’ll see percentages similar to flower, but much higher. A cartridge might be 80% THC.
Higher numbers mean more potent product. But remember, potency isn’t everything. A 30% THC flower with a poor terpene profile might feel less enjoyable than an 18% flower with the right terpenes for your body.
Terpene Profile
Not all COAs include terpene testing, but many do. This section lists the terpenes present and their percentages.
Common terpenes you might see:
- Myrcene (earthy, relaxing)
- Limonene (citrus, uplifting)
- Caryophyllene (spicy, soothing)
- Pinene (pine, alert)
- Linalool (floral, calming)
Terpene percentages are much smaller than cannabinoid percentages. A flower with 2% total terpenes is considered very terpene-rich. Most flower falls between 0.5% and 3% total terpenes.
The terpene profile helps explain why two strains with similar THC levels can feel so different. It also tells you what to expect in terms of aroma and flavor.
Contaminant Testing
This is where safety gets confirmed. California requires testing for several types of contaminants:
Pesticides: Labs test for dozens of specific pesticides. The COA will show either “Pass” or “Fail,” or list individual pesticide levels with pass/fail marks for each.
Microbials: This tests for harmful bacteria, mold, and yeast. Common tests include total yeast and mold count, E. coli, Salmonella, and Aspergillus (a dangerous mold).
Heavy Metals: Cannabis plants can absorb heavy metals from soil. Labs test for lead, arsenic, cadmium, and mercury. Results should show levels below California’s action limits.
Residual Solvents: For concentrates and cartridges, labs check for leftover chemicals from the extraction process. Solvents like butane, propane, and ethanol should be at safe levels.
Mycotoxins: These are toxic compounds produced by certain molds. The COA should show pass results for mycotoxin testing.
Foreign Material: This checks for things that shouldn’t be there, like hair, insects, or packaging material.
For most contaminant tests, you want to see the word “Pass” or “ND” (not detected). If any test shows “Fail,” the product shouldn’t be on dispensary shelves.
Moisture Content and Water Activity
These tests apply mainly to flower. They measure how much water is in the product.
Moisture Content: Shown as a percentage. Flower typically falls between 5% and 15%. Very dry flower (under 8%) may smoke harsh. Very wet flower (over 15%) risks mold.
Water Activity (Aw): This measures how available water is for microbial growth. California requires flower to have water activity below 0.65 to prevent mold. Lower numbers are safer.
These numbers won’t affect most buying decisions, but they’re useful if you want to understand product quality.
Reading a COA: Step by Step
Here’s a simple process for checking lab results:
Step 1: Confirm the product info matches what you bought. Check the product name and batch number.
Step 2: Look at Total THC (and Total CBD if relevant). This tells you potency.
Step 3: Check the terpene profile if available. Look for terpenes that match the effects you want.
Step 4: Scan the contaminant tests. Everything should say “Pass” or show levels below the action limits.
Step 5: If you see any “Fail” results or anything that concerns you, ask the budtender for more information or choose a different product.
Red Flags to Watch For
Most products at licensed dispensaries pass all tests. But here are some warning signs:
Missing or incomplete COA: If a dispensary can’t provide lab results, that’s a concern.
Old test dates: COAs should be relatively recent. Tests from over a year ago may not reflect the current product condition.
Failed contaminant tests: This should never happen with products on shelves. If you see a fail, report it.
THC numbers that seem too high: If flower claims 40% THC, be skeptical. Very few strains legitimately test that high. Inflated numbers sometimes indicate questionable testing practices.
No batch number match: Make sure the batch number on the COA matches your product packaging.
Where to Find COAs
There are several ways to access lab results:
QR codes: Many products have a QR code on the label. Scan it with your phone camera to view the COA online.
Dispensary websites: Some dispensaries post lab results on their online menus next to each product.
Ask your budtender: Staff can often look up or print COAs for any product in the store.
Brand websites: Some cannabis brands publish all their lab results on their own websites.
If you can’t find a COA anywhere, that’s a sign to shop somewhere else.
Lab Testing Builds Trust
Licensed dispensaries like Caña Sylmar only sell products that pass California’s strict testing requirements. This protects you from the risks that come with untested cannabis.
When you understand how to read a COA, you become a more informed consumer. You can verify that products match their labels. You can avoid anything that seems off. And you can shop with confidence knowing exactly what you’re getting.
The Bottom Line
Lab tests look complicated, but the basics are simple. Check the cannabinoid percentages to understand potency. Look at terpenes to predict effects and flavor. Make sure all contaminant tests show “Pass.”
You don’t need a chemistry degree to use this information. A quick review of the COA takes less than a minute and helps you make better choices. Next time you buy, take a look at the lab results. What you learn might surprise you.