Cannabis Lab Testing

Why Cannabis Gets Lab Tested

Regulated cannabis markets require licensed cultivators and manufacturers to test products at accredited third-party laboratories before sale. Testing verifies potency claims, screens for harmful contaminants, and builds consumer trust. In legal states, dispensaries can only sell products with a current Certificate of Analysis (COA) from an accredited lab.

What Labs Test For

A comprehensive cannabis test panel includes: cannabinoid potency (THC, CBD, CBN, CBG, and others), terpene profile, pesticide residues (over 60 compounds screened), heavy metals (arsenic, cadmium, lead, mercury), microbial contaminants (mold, yeast, E. coli, salmonella), residual solvents (for extracts), and mycotoxins. Some states require all of these; others only require potency and basic safety tests.

Understanding Potency Numbers

THC percentage refers to the concentration of tetrahydrocannabinol by weight. A 20% THC flower contains 200mg of THC per gram. However, the THCA-to-THC conversion must be considered — labs report both "THC" and "THCA" separately. Total potential THC = THCA × 0.877 + THC. CBD works similarly. Many products list "Total THC" which accounts for this conversion.

Reading a Certificate of Analysis (COA)

A COA includes: the testing lab name and accreditation, sample ID and collection date, product details, test methods used, individual cannabinoid results, contaminant test results (pass/fail), and lab director signature. QR codes on cannabis packaging often link directly to the COA. Always verify the COA matches the batch number on your product.

Lab Shopping and Quality Concerns

A known issue in the cannabis industry is "lab shopping" — finding labs that consistently return high THC numbers to satisfy marketing demands. Look for labs accredited by ISO/IEC 17025 or equivalent bodies. Independent advocacy organizations like SC Labs publish educational content about testing standards. When potency claims seem unusually high (35%+ THC), verify the COA carefully.