Differing test methods raises doubts about accuracy
Mandatory lab testing of cannabis is a cornerstone of most state programs that have legalized the sale of marijuana. Patients and consumers expect the test results on their cannabis products to reflect the safety and cannabinoid content but a report from CommonWealth Magazine has highlighted the problem with putting all your faith in the lab results. CommonWealth Magazine purchased samples of cannabis from dispensaries across Massachusetts and had the products re-tested for cannabinoid content and impurities at multiple labs. The test results show that some products contained less THC than advertised. Some samples were flagged for the presence of potentially harmful bacteria.
Roughly a dozen independent testing labs are now licensed to operate in Massachusetts. Currently, there is no state or national standard for testing cannabis for potency or contaminants. Each lab can choose which testing methodology to use. Some states have chosen to prevent labs from using specific technologies such as qPCR based on a belief that the method does not produce reliable or accurate results. Allowing labs in Massachusetts to use different methodologies means that one product could receive different lab results depending on which lab does the analysis. Some worry that this allows producers to go to multiple labs for testing and use whichever lab issues a positive result to begin selling their product.