Interpreting Your Potency Results Part I

An Exact Estimate - The THC level listed on the label simply does not tell a complete story.

A Certificate of Analysis from Lightscale Labs displaying the average levels of various cannabinoids contained in a batch of cannabis flower.

I bet you want what most smokers want: to know your cannabis product is safe, free of dangerous pesticides, and full of THC. You may not, however, be as interested in sorting through the details of the lab test results… but perhaps you should be. While most consumers remain at least partially interested in THC potency, a truly savvy smoker knows there’s a lot of nuance in how that potency can be reported.

The figure many buyers focus on is the average THC potency of a batch of cannabis flower. This Batch Average is the potency that ends up on the jar in the dispensary. If you’re buying a vape cartridge or edible, the Batch Average is the number printed on the label on back of the package. But because it’s nearly impossible to chemically test a cannabis nug or a gram of product without ruining it, and nobody has the time or money to test every single nug that comes off a plant, an entire 15lb batch of cannabis flower will be assigned the same Average THC potency. Meanwhile, a Production Batch of cannabis products can contain tens of thousands of vape cartridges or bottles of tincture or grams of shatter, which will all be assigned the same Average Potency!

So does every nug or vape cart in that one batch possess the same amount of THC? Obviously not.

Which is why I tell you this now, and may you never forget it: the THC level listed on the label simply does not tell a complete story.

How did these THC measurements add up to 22.9% Total Cannabinoids? Cannabis potency reporting can be deceiving.

To truly understand what a potency test result means, you have to consider several different factors, such as: How has your lab chosen to calculate “Total THC”? What is your body doing with these THC molecules, or, how are you metabolizing this chemical? How many samples from this batch were analyzed to get the Average THC Potency? And possibly the most important factor: how much of a gap exists between the Average Potency and the true THC content of the samples collected?

The more you understand how a lab tests for, calculates, and reports THC potency, the better prepared you’ll be to interpret test result data and ask follow-up questions of your testing lab. And it is really in your best interest to ask some follow-up questions, because as of right now, there are few reference methods and no nationally accepted standard for how to test cannabis. This means it's conceivable that you could take your product to 5 different labs and get 5 slightly different results.

What’s more, even if the testing at all 5 labs is done exactly the same way, chances are that the reporting will not be.

That’s why, in this series of articles about “Interpreting Potency,” we’ve laid out some of the ways cannabinoids can be measured, calculated, and reported.

The Best Estimate

The first important point you need to understand about the potency of THC (and all chemicals) in cannabis is this: the test result listed on every product, ever, is an estimation, and not an exact measurement.

Let’s imagine you’re buying oil in a vape pen from a dispensary, and that the cartridge is labeled with a potency of 64% THC. You would be tempted to assume (and rightly so) that 64% is the actual amount of THC in that vape cart. You’d probably also assume that 64% THC figure was the result of a test done on the vape cartridge you’re holding…

But that’s impossible. If that particular cartridge had gone to the testing lab, it wouldn’t be available at the dispensary. It would be in a chemical waste bin.

Maybe you’re a little savvier about the cannabis industry, and you know that 64% is the potency assigned to the entire production batch that the oil in this cartridge came from. You might also know that the 64% Average was calculated from the potencies of several different grams of oil, collected from across the production batch.

However, these are not the only complications that stand in the way of sussing out the true potency of your unique vape cart. On top of knowing how the batch of oil was sampled, you also need to know how the ‘Total THC’ was calculated. Fortunately, we will cover those calculations in the second article of this series.

Individual grams of oil taken from a large production batch will always contain at least slightly different amoutns of THC, and all chemicals.

The Take Away

It’s clear that precise and accurate test results for cannabis products depend not only on the integrity of the lab performing the analysis, but also the way the data is calculated, and presented. Results can become even more muddled by the fact that the average batch potency may not always accurately depict the true potency of each individual gram of product. When you also factor in that most chemical potency results are actually taken from the average of 2 different samples, each of which is a composite sample from several different sections across the production batch, you start to see just how complicated analytical test results can be to interpret.

The take-away is: with so many variables contributing to and altering the final reported cannabinoid potency, it's crucial that the calculations done to find that potency be as transparent and precise as possible. The more we educate consumers on how these factors affect reported THC, the more questions they can ask of the people testing their cannabis, and the greater our potential to move towards a national standard for analytical test results reporting.

Up Next: How does THC potency differ from Total THC?