Reading a Cannabis Certificate of Analysis

Key Sections of a COA

1. Header & Chain of Custody: Testing lab ISO 17025 certification, licensed producer, batch/lot number, sample weight, test date.
2. Cannabinoid Profile: HPLC quantitative mass percentages and decarb-adjusted totals.
3. Terpene Profile: GC-MS or GC-FID quantitative mass concentrations (mg/g or %).
4. Contaminant Safety Panels: Heavy metals, pesticides, mycotoxins, residual solvents, and microbials (Pass/Fail).

Active THC Calculation (Ohio & Industry Standard)

Raw plant material contains non-psychoactive THCA (tetrahydrocannabinolic acid). Upon thermal extraction, THCA undergoes thermal decarboxylation, releasing carbon dioxide (CO₂).

The molecular weight ratio yields the conversion factor:

Total Active THC = Δ⁹-THC + (THCA × 0.877)

Example Calculation

If a COA reports:

• THCA: 24.2% (242.0 mg/g)
• Δ⁹-THC: 0.52% (5.2 mg/g)

Total Active THC = 0.52 + (24.2 × 0.877) = 0.52 + 21.22 = 21.74%

Units, LOD, and LOQ Handling

• mg/g to Percent: $10\text{ mg/g} = 1.0%\text{ by weight}$.
• LOD (Limit of Detection): Smallest concentration the lab instrument can detect.
• LOQ (Limit of Quantitation): Smallest concentration the lab can accurately measure. Values below LOQ should be listed as < LOQ or Trace, not assumed zero.