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How to Read a Cannabis COA (Certificate of Analysis) in DC

A COA is your proof that a cannabis product has been independently tested. Here's how to read one and what to look for at DC dispensaries.

By DCWeedHub Editorial · Published · Updated

How to Read a Cannabis COA (Certificate of Analysis) in DC

Short answer: A Certificate of Analysis (COA) is a lab report on a specific batch of a cannabis product. DC law requires licensed testing labs to report THC and CBD concentration. It also requires them to test for contaminants, including mold, mildew, pests, mycotoxins, pesticides, heavy metals and residual solvents, against safety thresholds (D.C. Code § 7-1671.05). Since ABCA licensed DC's first testing lab in August 2024, products have had to be tested before they move through the medical market (ABCA notice, Aug. 30, 2024). Read a COA in this order: the batch match, potency, the contaminant panels, then the lab and date.

To buy from a licensed DC store, register first: start your ABCA registration.

What DC requires labs to test

D.C. Code § 7-1671.05 directs the rules for testing labs to require reports covering (D.C. Code § 7-1671.05):

  • Potency: THC and CBD concentration.
  • Growing inputs: whether the product is organic or inorganic, and the fertilizers used.
  • Contamination: mold, mildew and pests.
  • Safety thresholds: mycotoxins, pesticides, heavy metals and residual solvents.

The same section lets registered patients have products they bought from licensed stores tested by a licensed lab (D.C. Code § 7-1671.05). The detailed rules are in Title 22-C of the DC Municipal Regulations, chapters 64–66 (22-C DCMR). Chapter 65 was rewritten effective February 25, 2026 (73 DCR 2136). The specific numeric limits for each contaminant aren't reproduced here. They're UNKNOWN to this page; check the current DCMR text.

DC testing timeline

ABCA announced on August 30, 2024 that ClearSight Labs had been licensed as DC's first medical cannabis testing lab on August 16, 2024. It said products would need testing before transfer (ABCA notice). For how many labs are licensed now, check ABCA's license lists and our license lookup guide.

Reading a COA step by step

1. Match the batch

Check that the product name and batch or lot number on the COA match the package. A COA only describes the batch that was tested.

2. Potency panel

Look for THC, THCA, CBD and CBDA, and often "total THC" and "total CBD." THCA is the acid form in raw flower. Heat (smoking, vaping, baking) converts it to THC, and the molecule loses weight as it does.

Total THC = THC + (0.877 × THCA). The 0.877 factor is the molecular-weight ratio of THC to THCA: 314.45 ÷ 358.47 ≈ 0.877.

Worked example (ESTIMATE, illustrative numbers): a flower COA showing 0.5% THC and 22.0% THCA → 0.5 + (0.877 × 22.0) = 0.5 + 19.3 = 19.8% total THC.

Potency is listed as a percentage for flower and in milligrams for edibles and other dosed products. For what THC and CBD are, see CBD vs. THC.

3. Contaminant panels

Look for a result on each panel: pesticides, heavy metals, microbials (mold, yeast, bacteria), mycotoxins and, for extracts, residual solvents. Results are usually shown as "Pass," "ND" (not detected) or a measured amount next to the limit.

4. Terpenes (optional)

DC law doesn't list terpenes among required tests (D.C. Code § 7-1671.05), so many COAs won't include them. Terpene results describe aroma chemistry. They don't predict effects. See terpenes explained.

5. Lab and date

Check the lab's name, license or accreditation, the date the sample was tested, and a signature or authorization.

Red flags

  • The batch number doesn't match the package.
  • No lab name, or a lab that isn't licensed. Check ABCA.
  • Missing contaminant panels.
  • "Fail" on any panel.
  • Totals that don't add up when you run the formula.

Whether DC requires stores to show COAs to customers on request is UNKNOWN to us. We haven't found a rule saying so. Ask the store.

Frequently asked questions

What is a cannabis COA?

It's a lab report on one batch of product. In DC it covers potency and required contaminant tests (D.C. Code § 7-1671.05).

How do I calculate total THC?

Total THC = THC + (0.877 × THCA). The 0.877 factor is the molecular-weight ratio of THC (314.45) to THCA (358.47).

Does DC require cannabis to be lab-tested?

Yes. DC law sets testing requirements, and since ABCA licensed the first testing lab in August 2024, products must be tested before transfer (ABCA).

Can patients get their own product tested?

D.C. Code § 7-1671.05 lets registered patients have products bought from licensed stores tested by a licensed lab.

Keep reading

Sources

Last updated: October 26, 2026. Educational information only. 21+.