Potency test

Potency testing is the core of every hemp certificate of analysis. The lab weighs a sample, extracts the cannabinoids into a solvent, and runs the solution through a chromatograph that separates each compound and measures its concentration against calibrated standards.

The instrument choice changes what is measured. High-performance liquid chromatography runs at room temperature and reports acid forms such as THCa and CBDA separately from neutral THC and CBD. Gas chromatography heats the sample, which decarboxylates the acids, so it reports only the neutral forms as if the sample had already been heated. USDA accepts both, with the rule that non-decarboxylating methods calculate total THC as delta-9 THC plus 0.877 times THCa (7 CFR 990.1).

Hemp crop testing under state and federal plans must come from a laboratory registered with the DEA, though USDA has delayed enforcing that requirement until December 31, 2026 (USDA AMS). Finished product testing is governed by state rules, which vary widely (Cannabis Cannabinoid Res 2026).

A good potency report lists every cannabinoid the method covers, including ND lines, states the limit of quantitation, and expresses finished-goods results in milligrams per serving and per container so they can be compared with the label and the federal 0.4 mg cap.