How to read a COA: a section-by-section walk-through with the math

This page reads one certificate of analysis from top to bottom. The worked numbers use an illustrative tincture: a 30 milliliter bottle with a stated fill weight of 28.0 grams, 30 servings, labeled 1,500 milligrams CBD. Every conversion below uses the federal formulas in 7 CFR 990.1 and the per-container limit in Public Law 119-37, section 781.

What should the header and lab block show?

Check the lab, not the logo. Look up the certificate number in the accreditation body's directory and open the scope document; confirm it lists cannabinoid potency and the contaminant panels for the matrix on the report. A lab accredited for plant material only has stepped outside its scope when it reports on a gummy. The header should also show the lab's license number if its state requires one, and a report number unique to this document.

If the header shows the brand's name where the lab's should be, the document is an in-house report, not a third-party COA. Results vary between labs; NIST built its CannaQAP exercises to help cannabis labs "demonstrate and improve measurement comparability" (NIST CannaQAP), so the lab's identity is the first fact to pin down.

What goes in the sample ID and batch block?

On the example report the block reads: Batch 2026-TNC-0917, Sample ID L-48812, Matrix: tincture (MCT oil), Received 2026-09-19, Tested 2026-09-22, Sample received: 2 retail units, 28.0 g fill each. The fill weight is the number every later conversion depends on. A COA that reports results per gram but never states how many grams are in the container has handed that step to you; the label's net weight is the fallback.

Dates should run in sequence: manufactured, received, tested, then packaged for sale. A received date before the batch existed means the report belongs to another batch.

How do you read the cannabinoid potency table?

Worked example, CBD line. The report shows CBD 5.36 percent, which is 53.6 milligrams per gram. Multiply by the 28.0 gram fill: 53.6 x 28.0 = 1,500.8 milligrams CBD per container. Divide by 30 servings: 50.0 milligrams per serving. The label claim of 1,500 milligrams is within 0.1 percent of the measured value. For reference, FDA's 2020 sampling counted a product as accurate when it fell within 20 percent of its label, and only 45 percent of products with a stated amount did (FDA 2020 report).

Watch the units on liquids. Some labs report milligrams per milliliter for tinctures. That figure already includes the oil's density, so multiply by milliliters, not grams. Never assume 1 milliliter weighs 1 gram for an oil; use whichever unit the lab reported and the matching container measure.

Read the whole table, not just the headline. CBDA, CBG, CBN, CBC and THCA each tell you something: CBDA shows how much of the extract was never decarboxylated, CBN shows age or heat exposure, and THCA feeds directly into total THC.

How is total THC calculated on the report?

Now carry it to the container. 0.0975 milligrams per gram x 28.0 grams = 2.73 milligrams total THC per bottle. The amended federal hemp definition excludes final products containing "greater than 0.4 milligrams combined total per container" of total tetrahydrocannabinols including THCA (P.L. 119-37, section 781). This bottle, at under 0.01 percent THC, carries 6.8 times the cap. Per serving it is 0.09 milligrams, which is why a percent or a per-serving figure can look harmless while the container fails.

The cap applies from December 11, 2026 under Public Law 119-103, which limits the section 781 amendments until that date to products containing cannabinoids the plant cannot naturally produce (P.L. 119-103, section 2019). A product that passes the 0.3 percent standard by a factor of 30 can still fail the per-container standard by a factor of 7; the two tests measure different things.

What do LOQ and LOD mean on the report?

Work out the LOQ a container needs. Divide the cap by the fill weight: 0.4 milligrams / 28.0 grams = 0.0143 milligrams per gram, which is 0.00143 percent or about 14 parts per million. For a 30 count gummy jar at 4.0 grams per piece, 120 grams, the required LOQ is 0.4 / 120 = 0.0033 milligrams per gram, about 3.3 parts per million. If the report's LOQ is higher than that figure, ND does not demonstrate compliance for that container.

Measurement uncertainty belongs beside every result near a limit. The federal rule defines it as the parameter that characterizes the dispersion of values that could reasonably be attributed to the measured quantity (7 CFR 990.1). A result of 0.38 milligrams per container with an uncertainty of plus or minus 20 percent spans 0.30 to 0.46 milligrams; the report should say how the lab calls that case.

How do you read the contaminant panels?

Residual solvents should match the extraction method. On the example report the solvent panel shows ethanol at 410 micrograms per gram against Washington's 5,000 limit, benzene ND at an LOQ of 0.5 against a 2.0 limit, and butanes ND. That pattern fits an ethanol extraction. A hydrocarbon result on a product described as CO2-extracted is a question for the supplier. Mycotoxins should show aflatoxins and ochratoxin A each under 20 micrograms per kilogram (WAC 314-55-102).

Pesticide panels are the longest section. The report should list each compound with its own limit and LOQ rather than a single "pesticides: pass" line, and the panel should be run on the finished matrix. A panel of 59 compounds and a panel of 13 are not the same test. The named standard, whether a state rule or the lab's own, should be printed at the top of each panel.

What do pass/fail, signatures and the QR code confirm?

The approval date should follow the test date. The QR code should resolve to the laboratory's own hosted copy of this report, or to a page that links to it, with the same report number and batch number. A code that opens a brand page, a generic "lab results" gallery, or a PDF with the batch number removed does not verify anything. Scan it, compare the report number, and save the file with the purchase date.

Finish with the three-line check. Milligrams per gram equals percent times 10. Total THC equals delta-9 THC plus 0.877 times THCA (7 CFR 990.1). Milligrams per container equals milligrams per gram times fill weight, and total THC per container must be at or below 0.4 milligrams to stay inside the federal hemp definition after December 11, 2026 (P.L. 119-103). The lab testing hub covers accreditation, contaminant limits and retesting in depth.