Editor's note: This article has been reviewed and updated for accuracy in 2026. Can you determine how much THC is present in your cannabis strain? Well, it is difficult to analyze the THC% in cannabis, unless you test the samples. If you are buying cannabis products from a certified medical dispensary, you can check the label to read the “Total THC” composition. However, as there is no official industry standard for testing THC in Cannabis, different producers use different testing procedures and calculate the % of THC in different ways. The best over-the-counter test kits for consumers consist of tCheck, CannaDx by MyDx, and HiGrade. They're the best reviewed and top selling, but they each go about analyzing THC potency in different ways and each come with their own unique feature sets. Why it is Important to Test THC Potency of Cannabis The chemical makeup of marijuana for medical use must be precisely analyzed. The cannabinoid profile of cannabis is like a fingerprint, made up of more than 70 compounds, the ideal dosing of which can impact the patient’s treatment.