How Accurate is Lab Testing?

The same sample of cannabis flower was tested at five different private cannabis testing facilities in South Africa and produced a wide variability in THC results from 13.9% to 23.9% as can be seen in Figure 1 below. The CBD content varied from 0.003% to 1%. 

In an independent study we found that only 2% of edible cannabis products were labeled accurately in South Africa. 23% of those products were under labeled and 60% were over labeled in terms of THC content. This is largely because labs are often producing different results with the same samples, effectively invalidating the legitimacy of laboratory testing altogether. Another issue facing testing labs today is producing homogeneity in a sample that is truly representative of one batch. Profit-motivated or unknowing clients will submit only the top part of their most robust plant and claim that this is representative of their entire crop, leading to inflated and misleading test results.

The harder one looks, the clearer it becomes; cannabis testing labs – for the most part – are not as reliable and consistent as consumers would like, but could the plant itself be contributing to the challenge?

Same strains, different results

Beyond testing practices, cannabis itself is complex and unruly— there is a wide variability in the chemical profile of a particular strain, and even when both samples are harvested from the same plant. Buds found at the top of the plant will have a different profile than the ones founds tucked away near the bottom as a direct result of varying light exposure, temperature, and humidity. Knowing this, it should then come as no surprise to find that the Sour Diesel picked up from the cannabis club six months ago could feel a little different than the one you picked up just last week. This further proves the notion that even with consistent and reliable genetics, there can be a wide range of variability in a plant’s total chemical profile. For example, grow two clones cut from the same mother plant in slightly different environments and they will exhibit different chemical profiles, which will subsequently result in different effects in the user. For cultivators, accurate and reliable testing during the final phases of cannabis growth cycle is critical. It can help them harvest at the ideal chemical profile and it can be used to demonstrate the quality of their final product to their clients prior to purchasing. For patients and consumers, accurate and reliable testing data is critical to ensuring a consistent and effective cannabis experience. 

The challenge for individuals and industry professionals alike has been the lack of a go-to resource for strain chemical profile data and associated effects. Scientific data collection is in its early stages, and there is a limited ability to capture reliable user-generated scientific information on a large scale—leaving people to rely on word-of-mouth or trial-and-error to find the strains that work best, by relieving specific conditions or producing targeted effects. As the cannabis community explores the complex world of cannabinoids and terpenes, reliable data and the ability to identify the detailed ‘cannabis profile’ of a given strain will be critical to helping people take advantage of cannabis’ increasing array of medicinal benefits. These challenges and market dynamics have given rise to CannaLab, The Lab For the people – offering an affordable, transparent, and reliable way to consistently test cannabis in a convenient way.

CannaLab analyzes any strain’s Total Cannabis Profile (TCP), quickly, giving you the information you need to predict how a strain will make you feel and what symptoms it will alleviate. 

CannaLab is a practical option for patients, recreational users, cannabis clubs, commercial growers, and even small scale cultivators who want to analyze their cannabis at a primary screening level.

 This is the kind of transparency and convenience that we can all rally behind. By allowing anyone to test their cannabis at any time, CannaLab is empowering the industry enabling access to affordable testing for all.

CannaLab resulting analysis, provides a summary of the medically relevant cannabinoids and terpenes in the sample which have been shown to play a key role in the resulting cannabis experience. Our unique algorithms, coupled with our partner databases then interprets this information, allowing a CannaLab to track and predict how the sample will make you feel and what symptoms it will alleviate. This system effectively enables users to hone in on the strains, or Total Cannabis profile, that work best for them.

When a cannabis sample is tested by CannaLab, it is analyzed using our digital gas-flow system that supports the chemical release process, essentially volatilizing the compounds for analysis by our formulated polymer based sensors. The vapors cause swelling, which induces quantifiable resistance changes at a sensitivity up to 500 parts per billion. Within a very short space of time, an in-depth analysis of the sample is produced and digitised including exactly what the information means and why users should care. 

Our Partners have secured over 350 unique strains of cannabis from dispensaries across the globe. A reference database was compiled by calculating the actual chemical composition of these strains using gold standard Gas Chromatography (GC) methodologies published by Resktek Corporation ( and correlating that data with CannaLab’s 16 channel sensor response patterns to generate a Delta R/R fingerprint of the same exact sample. They tested for 3 cannabionoids and 20+ terpenes found in the plant using GC. We exposed 10 replicates of 50 mg of cannabis flower to generate a fingerprint for each strain. By applying specific algorithms to sensor formulations developed in collaboration with our partner, Next Dimension Technologies based in Pasadena, CA, they have identified proprietary polymer formulations on our sensors that are most effective for analyzing cannabis samples. Next generation sensors will build on this foundation to improve accuracy and specificity for various analytes in cannabis.

Why 0.877?

A lot of customers ask about “Δ9-THC Potential” on lab reports and why we use 0.877 to calculate it. This post from Confidence Analytics explains the chemistry and the math in straightforward terms.

“As you may know, the plant-made versions of the major cannabinoids, sometimes called cannabinoid acids, need to be “decarbed”, or decarboxylated, before they can assume their full active effects. This decarboxylation is why it’s called a decomposition reaction — one molecule becomes two. In our case, one of these molecules is always CO2, (carbon dioxide being the source for decarboxylate). The other molecule is the “active” or “neutral” cannabinoid itself.

[THC Potential = THC + (0.877 * THCA)]

The number 0.877 is actually fixed in nature, and it’s based on the ratio of the masses of the cannabinoid molecules. Most major cannabinoids (THC, CBD, CBG, CBC, but not CBN) have the same molecular formula: C21H30O2, for 21 carbons, 30 hydrogens, and 2 oxygens. The equivalent cannabinoid acids (THCA, CBDA, CBGA, and CBCA, respectively) are “neutral” cannabinoids that are “wearing” a CO2 molecule, changing their molecular formula to C22H30O4 with the addition of one carbon and two oxygens.

Each element in a molecule has a measurable weight, and the most common weight of an element is usually the largest number in an element’s box on the periodic table. Carbon has an atomic mass of approximately 12.011, hydrogen about 1.008, and oxygen almost exactly 16.

We can calculate how much each molecule of THC weighs, like this:

THC’s molecular weight = 21 Carbons (12.011) + 30 Hydrogens (1.008) + 2 Oxygens (16.000)

THC’s molecular weight = 314.47

We can calculate the same for THCA:

THCA’s molecular weight = 22 Carbons (12.011) + 30 Hydrogens (1.008) + 4 Oxygens (16.000)

THCA’s molecular weight = 358.48

The molecule released during “decarb”, CO2, has a molecular weight of about 44.01. If we add THC’s 314.47 and CO2’s 44.01, we get the molecular mass of THCA, 358.48. The universe is making sense! So far so good. If we take this a step further, we realize that THCA is, in fact, not entirely THC. It’s only 314.47 / 358.48 = 0.8772 or 87.72%. There’s our 0.877! The remaining 12.28% is CO2, which bubbles away as a gas during decarboxylation – the bubbling of a full melt hash or a dab on a hot nail illustrates this process.

Now, the goal of the available THC calculation is to find, under absolutely ideal conditions, the maximum amount of “active” THC that can be derived from a sample. If THCA is only 87.72% THC, it only makes sense that we account for that fact in our available THC calculation; Multiply the amount of THCA by 0.877 before adding it to the amount of already “activated” THC. Put another way, a gram of 100% pure THCA contains 0.877 grams of THC and 0.123 grams of CO2.

The same exact “activation multiplier” can be used to calculate available CBD, CBG, or any other cannabinoid with a molecular formula of C21H30O2. Some may have noticed that the American Herbal Pharmacopeia blurb about available cannabinoid content features a multiplier of 0.878 for CBGA; this is because CBGA’s molecular structure contains two more hydrogen atoms, for a formula of C22H32O4. When CBGA decarboxylates into CBG, the two hydrogen atoms are retained, and CBG thus has two more hydrogen atoms in its structure than THC or CBD. The same math from above with the molecular weights of CBGA and CBG (360.75 and 316.74 respectively) yield a conversion factor of 0.8780, slightly different than the 0.877 for THCA to THC.

For the -varin class of cannabinoids, THCV being the most well-known (but also including CBDV, CBGV, CBCV, and their respective acids CBDVA, CBGVA… etc.), we need a different activation number because the molecular masses aren’t the same: cannabivarins are missing two carbons and four hydrogens compared to their regular cannabinoid cousins, giving us a molecular formula of C19H26O2 (mass of 286.42), and C20H26O4 (mass of 330.43) for their acids. Our “activation multiplier” for the -varin class is 0.8668 instead of 0.8772. Close, but not the same!

We hope this answers some of your questions about our favorite herbal product, or perhaps piques your interest to learn more about chemistry.

The seemingly arbitrary number 0.877 is a ratio of molecular masses, specifically that of THC divided by that of THCA. If you multiply the amount of THCA by 0.877 and add the amount of already “active” THC, you find the maximum amount of THC remaining after complete decarboxylation. THCA is about 87.7% THC and 12.3% CO2 by mass.”

Thanks Confidence Analytics!

Let’s talk about how CannaLab might help you.

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