How to Read a Cannabis Lab Report (Certificate of Analysis)

Overview

A Certificate of Analysis (COA) is a document from an independent laboratory that verifies what is in a cannabis or hemp product. Learning to read COAs helps you verify product claims, identify potential safety concerns, and make informed purchasing decisions. This guide explains each section of a typical lab report and what to look for.

Why Lab Testing Matters

The cannabis and hemp industry lacks comprehensive federal regulation. Product quality and accuracy vary significantly between manufacturers. Lab testing provides:

• Verification that products contain what labels claim
• Detection of harmful contaminants
• Confirmation of legal compliance (THC levels for hemp products)
• Objective data for comparing products

A 2017 study published in JAMA found that only 31% of CBD products tested had accurate labeling, with some containing no CBD and others containing unlisted THC [1]. Third-party testing helps identify these issues.

Finding a Product's COA

Reputable manufacturers make COAs accessible through:

• QR codes on product packaging
• Product pages on company websites
• "Lab Results" or "Test Results" sections on websites
• Direct request to customer service

If a company cannot provide a COA, this is a significant concern about product quality and transparency.

Key Sections of a Lab Report

1. Laboratory Information

What to look for:

You can verify lab accreditation through state regulatory databases or accreditation bodies like A2LA (American Association for Laboratory Accreditation).

2. Sample Information

This section identifies what was tested:

• Sample ID/Batch number: Should match the number on your product
• Sample name: Product name as submitted by manufacturer
• Sample type: Product category (flower, oil, edible, etc.)
• Date received: When the lab received the sample
• Date tested: When analysis was performed
• Date reported: When results were issued

Verification tip: The batch number on your product should match the batch number on the COA. If they don't match, the COA may not apply to your specific product.

3. Cannabinoid Profile

This section shows the concentrations of cannabinoids detected in the product.

Common cannabinoids tested:

Understanding the numbers:

• mg/g: Milligrams per gram of product
• mg/mL: Milligrams per milliliter (for liquids)
• %: Percentage by weight
• ND: Not detected (below detection limit)
• LOQ: Limit of quantitation (smallest amount reliably measured)

Calculation check: For a product claiming 30mg CBD per serving, verify:

• Find total CBD in mg/g or mg/mL
• Multiply by serving size
• Result should approximately match label claim (within 10-15% is typical tolerance)

4. Total THC Calculation

For hemp products, total THC determines legal compliance. Labs calculate this as:

Total THC = Delta-9 THC + (THCA × 0.877)

The 0.877 factor accounts for the molecular weight difference when THCA converts to THC. This "total potential THC" must be at or below 0.3% for the product to qualify as legal hemp under federal law [2].

5. Contaminant Testing

Quality labs test for various contaminants. Not all tests are required in all states, so coverage varies.

Pesticides

Tests for residual pesticides that may have been used during cultivation.

• Units: Usually parts per billion (ppb) or parts per million (ppm)
• Action limits: Each pesticide has maximum allowable levels
• Result: Pass/Fail or specific concentration detected

Common pesticides tested include myclobutanil, bifenthrin, imidacloprid, and dozens of others. A "pass" result means levels are below regulatory limits, not necessarily zero.

Heavy Metals

Tests for toxic metals that can accumulate in cannabis plants from soil or water.

Results are typically reported in ppm or ppb. Each has established maximum limits in regulated markets.

Residual Solvents

Important for concentrates and extracts made using solvents.

Common solvents tested:

• Butane, propane (BHO extraction)
• Ethanol (alcohol extraction)
• Acetone, hexane, isopropanol

High residual solvent levels may indicate incomplete purification. Limits are typically based on FDA and ICH (International Council for Harmonisation) guidelines [3].

Microbial Contamination

Tests for harmful microorganisms:

• Total aerobic count: Overall bacterial load
• Total yeast and mold: Fungal contamination
• E. coli: Specific pathogenic bacteria
• Salmonella: Specific pathogenic bacteria
• Aspergillus: Specific harmful mold species

Results show colony forming units per gram (CFU/g) or indicate presence/absence for pathogens.

Mycotoxins

Toxic compounds produced by certain molds:

• Aflatoxins (B1, B2, G1, G2)
• Ochratoxin A

These are carcinogenic and have strict limits. Testing is particularly important for products stored in humid conditions.

6. Terpene Profile (Optional)

Some labs test for terpenes—aromatic compounds that contribute to flavor and may have their own effects.

Common terpenes:

• Myrcene
• Limonene
• Caryophyllene
• Linalool
• Pinene

Terpene testing is not required for safety but can be useful for understanding a product's characteristics.

Red Flags to Watch For

COA Concerns

• Old test dates: COAs more than 12 months old may not reflect current product quality
• Batch mismatch: COA batch number doesn't match product
• Missing tests: Incomplete contaminant screening
• Unknown lab: Lab cannot be verified through state databases
• Low resolution/edited appearance: May indicate falsified documents

Result Concerns

• THC above 0.3%: Product is not legal hemp
• "Fail" on any contaminant test: Product did not meet safety standards
• Large discrepancy from label: More than 20% difference between tested and labeled potency
• No detection of claimed cannabinoids: Product may not contain what's advertised

Verifying COA Authenticity

To confirm a COA is legitimate:

1. Check the lab's website: Most labs maintain searchable databases of reports
2. Call the lab: Provide the sample ID and ask them to verify
3. Look for accreditation: Verify the lab is ISO 17025 accredited
4. Check for state licensing: Confirm the lab is licensed in states where required

What Different Products Should Test For

Summary

A Certificate of Analysis provides objective verification of product contents and safety. When reviewing a COA, check that the batch numbers match, verify the lab's credentials, confirm cannabinoid levels match label claims, and ensure all contaminant tests show passing results. If a manufacturer cannot provide a current, verifiable COA, consider purchasing from a more transparent source.

References

1. Bonn-Miller MO, Loflin MJE, Thomas BF, Marcu JP, Hyke T, Vandrey R. Labeling Accuracy of Cannabidiol Extracts Sold Online. JAMA. 2017;318(17):1708-1709. doi:10.1001/jama.2017.11909

1. U.S. Department of Agriculture. Establishment of a Domestic Hemp Production Program. 7 CFR Part 990. Federal Register, Vol. 86, No. 11, January 19, 2021.

1. International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). Q3C(R8) Guideline for Residual Solvents. 2021.

1. Americans for Safe Access. Patient's Guide to Lab Testing Cannabis. https://www.safeaccessnow.org/cannabis_testing

1. American Herbal Products Association. Recommended Methods for Testing and Quality Control of Cannabis Spp. 2018.