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Ace your next audit with our Dos and Don’ts for US cannabis testing labs


canabis testing lab image



Most existing cannabis labs will not make it

The US cannabis testing industry suffered a shock earlier this summer, when a leading lab closed down, blaming a lack of regulatory action and the practice of ‘lab shopping’ for putting ethical laboratories in peril. “Most existing cannabis labs will not make it”, said the laboratory’s chief science officer. “When people are able to test compliance samples at multiple labs and pick the most favourable result for sale, then it makes it very difficult for labs with integrity to get on the playing field.”


But what steps can good laboratories take to ensure they survive this challenging environment? And with commercial pressure on them to win business and be competitive, how can they be certain of passing their next official audit? Here, experts in ISO accreditation from LGC Dr Ehrenstorfer and LGC AXIO Proficiency Testing share some key Dos and Don’ts, based on our five decades of experience in analytical testing.





1.      Ensure you have the proper paperwork for your reference materials (RMs), including a robust and accurate Certificate of Analysis - with measurements carried out in accordance with ISO/IEC 17025 and ISO 17034 accreditation.


Every single product that a laboratory makes or analyses should have a paper trail

Complying with both ISO/IEC 17025 and 17034 standards depends largely on a lab’s ability to prove its documented data quality, which begins with having procedures clearly written out, a quality management plan and a management review plan. Every single product that a laboratory makes or analyses should have a paper trail, and labs receiving samples should have a chain of custody – showing a sample ID, when and where it was collected, how it was transported, who received it, and the kind of conditions it was stored in. It’s also critical that the analysis done on the sample, and any preparation that happens, such as subdivision, is very clearly documented. Therefore, if an analytical result on a sample is challenged – even in court - the lab can present evidence of every aspect of that sample and its analytical value.


2.      Train and educate your team on the right steps, and improve their expertise


Laboratory staff need to know the value of using reference materials correctly, and of stating correct values rather than - for example – amplifying the THC content of a sample. If trained properly, your staff will be concerned about measurement integrity and – if pressured by a manufacturer to elevate THC levels on a readout - will say “No”. They will understand best practice, and ethics, as well as the effect that fraud can have on a company’s ability to continue trading. One excellent introduction to these issues is provided by the Quality Module within CannLearn – the free app-based microlearning course for cannabis scientists developed by Dr Ehrenstorfer and the UK National Measurement Laboratory.


3.      Use Proficiency Testing schemes to assure the quality of your analytical data.


Laboratories need to demonstrate that their scientists are competent – and developing competence can be achieved with the help of proficiency testing (PT). One of the main criteria for becoming an ISO/IEC 17025-accredited laboratory is running PT samples for each of the processes and analytes in your laboratory. Regular use of a high-quality PT programme such as the AXIO cannabis scheme therefore enables laboratories to monitor their performance continually, and provides vital information on technical issues and methodologies.


4.      Use ISO 17034 Reference Materials to reduce uncertainty, giving you confidence in your results.


By choosing an ISO 17034 reference material, a laboratory knows its total combined uncertainty, whereas a non-ISO 17034 reference material only gives characterisation uncertainty – meaning that other factors are going unseen. When a manufacturer asks a laboratory to overstate the THC potency of a cannabis sample, it adds even more uncertainty to the measurement. Having an ISO 17034 reference material not only gives greater clarity, but it can also help laboratories say confidently to customers: “This is the correct value, and the correct uncertainty.” The majority of Dr Ehrenstorfer’s comprehensive range of reference materials for analytical testing of cannabis-related products are produced under the scope of ISO 17034.

Using a 17034-certified RM not only gives greater clarity, but it can also help laboratories say confidently to customers: This is the correct value, and the correct uncertainty


5.      Check for any contamination, such as pesticides


Lab shopping isn’t just about misrepresenting THC potency levels. Some customers will also ask laboratories to underestimate levels of contaminants in their products, and might look for those that employ less sensitive analytical techniques and don’t use ISO 17034 reference materials – because, on paper, it will look less like the analytical data has been falsified. Also, as a laboratory director recently pointed out in Cannabis Industry Journal, “Labs that inflate potency are more likely to ignore the presence of contaminants”, such as pesticides, heavy metals and aflatoxins. This increases the risks to consumers, as well as the likelihood of those labs being decertified.

Labs that inflate potency are more likely to ignore the presence of contaminants such as pesticides, heavy metals and aflatoxins, increasing the risks to consumers


6.      Follow state protocols for compliance sampling and testing


One significant problem for US cannabis laboratories is that testing regulations vary widely across the country. With so many methods available, less reputable labs might be tempted to use a test method that is less stringent than that required by the state. But with state-specific reference materials mixtures now available, it’s never been easier to follow local protocols: Dr Ehrenstorfer has developed more than 140 mixtures conforming to cannabis testing requirements in 19 US states – covering potency, pesticides, residual solvents, mycotoxins and heavy metals.





1.      Test without having the proper documentation


In this scenario, laboratory directors need to think about their legal liability, should something go wrong. Not having the correct documentation to show state auditors or lawyers means that it’s simple to make a case that a lab may have falsified testing results – with potentially catastrophic consequences for its reputation, as well as its criminal and legal liability. Every Dr Ehrenstorfer product comes with a Certificate of Analysis, which provides a full description of the material it relates to, as well as a summary of the analyses undertaken during the characterisation process.


2.      Use reference materials that aren’t ISO certified


It seems strange that some laboratories may choose not to work with ISO-certified reference materials. Those that decide to manufacture their own RMs are unlikely to have the resources and experience to put them through the rigorous quality control processes that commercial products have to undertake. Using the wrong RM can ultimately result in costly laboratory downtime if the other elements in the flowpath are contaminated. Moreover, demonstrating the traceability of a home-made product – as well as attempting to validate testing methods using one - is not just a major headache. It’s also a big red flag for any state auditor.


Laboratories that manufacture their own RMs are unlikely to have the resources and experience to put them through the rigorous quality control processes that commercial products have to undertake


3.      ‘Pass’ contaminated cannabis products


It’s understandable that labs operating in a crowded market don’t want to turn down business – but waving through a contaminated product that could subsequently make people sick is just inviting legal action and de-certification. And, yes, ethical considerations matter, too. Many cannabis products are for medicinal use, and if the heavy metals, pesticides or solvents present in that batch end up making someone with a compromised immune system even more ill…. Well, let’s just say that was never the goal of medicinal cannabis.


4.      Mislead on THC potency levels just to accommodate a customer


It’s a misconception that the higher the potency of a cannabis product, the better it is. With medicinal cannabis, patients depend on labs to measure THC content accurately, so that the products they use are at the correct therapeutic levels for their conditions. There are also clear dangers in understating potency levels – for example, drivers who are more intoxicated than they think causing an accident, harming themselves and others. There’s also evidence that laboratories are underestimating THC levels in hemp and CBD products – with potentially adverse consequences for consumers.


5.      Put profit before integrity, or take risks that will damage your lab’s reputation


The value of the US cannabis market is expected to reach $40 billion in 2030, but bad laboratory practices risk seriously damaging the industry’s reputation – and therefore consumer confidence and profitability. After years of struggle to legalise recreational and medicinal cannabis across the US, and the millions invested in product development and lab set-up costs, now is not the time for risky, short-term profit. The number of new laboratories on the scene is also an excellent reason to associate your company clearly with quality and integrity. After all, if a lab does something to damage its reputation, there are plenty of other places for customers to go – meaning that ‘bad’ labs can find themselves out of business very quickly.



For more information on how Dr Ehrenstorfer can support your laboratory’s cannabis testing, click here, or follow us on Linkedin for advice and insights on running your cannabis testing lab. For more information on how proficiency testing can help ensure your laboratory’s quality, visit the AXIO cannabis page


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