How to Read a THCA Certificate of Analysis (COA): Full Guide

A Certificate of Analysis (COA) is a third-party lab report that tells you exactly what's in a THCA product. It's the primary way buyers verify that a product is what it claims to be — and that it's federally compliant. Here's how to read one.

What Is a COA?

A COA is issued by an accredited third-party laboratory that tests the product independently from the vendor. Reputable labs include Steep Hill, ProVerde, ACS Laboratory, and Cannalysis, among others. The key word is third-party — vendor-claimed numbers without independent lab verification are meaningless.

Potency Panel: What to Look For

The potency panel lists cannabinoid percentages. For THCA flower, the critical numbers are:

THCA %

This is the main number you'll see marketed. Quality THCA flower typically runs 20–30%. Above 30% is exceptional. Be skeptical of anything claiming 35%+ without a credible COA — potency inflation is common in this market.

Delta-9 THC %

This is the compliance number. For hemp-derived products, Delta-9 THC must be below 0.3% on a dry-weight basis. If this number is missing or above 0.3%, the product is federally non-compliant.

Total THC

Some COAs show a "total THC" calculation: Total THC = Δ9-THC + (THCA × 0.877). Under this calculation, a product with 25% THCA and 0.1% Delta-9 would show ~22% total THC. This number is used by some state regulators. It does NOT affect federal hemp compliance under the Farm Bill, which only looks at Delta-9 THC.

Other Cannabinoids

Good COAs list CBD, CBG, CBN, CBC, and other minor cannabinoids. These don't indicate quality on their own, but a full panel shows the lab ran comprehensive testing.

Terpene Panel

Not all COAs include terpene testing — it's optional but a strong quality signal. Terpenes drive flavor, aroma, and the nuance of effects. A vendor who pays for terpene testing cares about product quality. Look for:

Total terpene % (good flower often shows 1–3%+)
Dominant terpenes by name (myrcene, limonene, caryophyllene, linalool, etc.)

Pesticide Panel

Lists pesticide residues in the flower. Results should show "ND" (not detected) or levels below the state action limits for each compound. Many budget vendors skip pesticide testing — it's expensive. Premium vendors run full panels.

Red flag: Any detected pesticide above action limits is a dealbreaker.

Heavy Metals Panel

Cannabis plants absorb heavy metals from soil. The panel tests for lead, cadmium, arsenic, and mercury. Results should be ND or below limits. Especially important for concentrates, which amplify everything present in the starting material.

Residual Solvents Panel

Only relevant for solvent-extracted products (concentrates, vapes, edibles). Tests for residual butane, propane, ethanol, and other solvents. Results should be ND. For raw flower, this panel isn't needed.

Microbials Panel

Tests for mold, yeast, E. coli, salmonella, and other pathogens. Less commonly included, but important — especially for immunocompromised consumers. Should show ND or below limits.

What to Check on Every COA

Lab accreditation — Is the lab ISO 17025 accredited? Legitimate labs list their accreditation number.
Test date — Avoid COAs older than 12 months for active products. Old COAs don't tell you about the current batch.
Batch/lot number — Should match the product you're buying. Generic COAs that apply to all products are a red flag.
Sample collection method — Did the lab collect the sample or did the vendor submit it? Lab-collected samples are harder to manipulate.
QR code or verification link — Legitimate COAs can be verified directly on the lab's website. Photoshopped COAs often lack verifiable links.

Common COA Red Flags

Delta-9 THC above 0.3%
THCA % suspiciously high (35%+) without a credible lab
Test date more than 1 year old
Missing batch/lot number
Lab name that doesn't appear in state or ISO databases
No link to verify on the lab's website
Pesticide or heavy metal panel showing detected results above limits

When you find a vendor with clean, current, fully-paneled COAs from accredited labs — that's a vendor worth buying from. Browse lab-tested THCA vendors →