DNA-Based Cannabis Testing Technology

Posted by Milan Patel on June 22, 2018

Cannabis Plant


Cannabis is now a rapidly-growing industry with a myriad of state regulatory requirements mushrooming up in its wake. Medicinal cannabis undergoes lab testing, requiring the hiring of qualified individuals who understand lab operations as well as the quality and spectrum of various testing procedures.  

Laboratories involved in the comprehensive testing of cannabis will typically test cannabis for residual solvents, physical and microbial contamination, potency, and terpenes. Some of the procedures involved in the microbial testing of cannabis include statistical sampling, relevant microorganism testing, and sound assay design and validation.

DNA-based tests are the current preferred state-of-the-art method and have proven to be imperative to patient safety. They are widely used, accepted, and peer-reviewed, and have been used for decades in other industries for similar purposes with great success.

One DNA-based technology is the quantitative polymerase chain reaction (qPCR) that deduces the number of colony-forming molds on cannabis plants. The qPCR technology is newer than culture-based testing, but it has actually been around for many decades -- since the early ‘80s – and has been extensively used to detect pathogenic microbes in the food and medical industries.

Drawbacks of qPCR Technology

So why hasn’t the cannabis testing market fully embraced qPCR as the go-to testing method? According to cannabis testing laboratories across the country, the biggest reason is the incremental cost per test. It cost approximately $10 to run qPCR versus the low cost of plating on good old petri dishes.

New lab equipment tends to be expensive, and the average cost of a lab-quality, brand new qPCR instrument can be expensive. A used machine system can range anywhere from approximately $15,000 at the low end to upwards of $30,000. New qPCR thermocyclers with 384-well blocks tend to be more expensive ($68,747) than those with 96-well blocks ($55,700).

This is just the cost of the thermocycler. There are also a few more hidden costs that are far less obvious as they are spread over the years. For example, the qPCR reagents are pricey. So, if a lab opts for the 384-well cycler, an estimated break-even point occurs with the 77th full qPCR plate. That corresponds to approximately 29,600 reactions. If we were to include the costs of primers, probes and labor costs, the number of reactions needed to break even would increase.

While these numbers are representative rather than absolute, it demonstrates that it is worthwhile to take time to do some math on how many reactions you will be performing with your new thermocycler. Maybe qPCR is not the best answer for cannabis labs.

So should labs go back to relying on petri dish testing for their microbial testing needs? This method is outdated and ineffective. Results can take days and be unreliable, producing false negatives or false positives.

Affordable DNA-Based Cannabis Testing Kits

When it comes to consumer safety, of course the labs testing cannabis should employ the best available technology, and that means DNA-based testing. How can the industry access the specificity, sensitivity and overall quality of DNA testing and still be attentive to the margins? PathogenDx DNA-based testing is the answer.

PathogenDx provides state-of-the-art performance. In addition to being able to test for over 20 different microbials simultaneously, PathogenDx testing kits provide maximum protection – down to 0.1 CFU for pathogenic organisms. PathogenDx tests are fast and are complete in 6 hours from raw sample to result, and the multiplex solution tests all state-regulated microbial organisms in one simple test.

PathogenDx’s affordable, simple, and effective testing can be scaled for testing facilities of all sizes. Whether you need to test an individual plant, a small grow house, an entire orchard, or large agricultural fields, these products will serve you well.

This technology provides people involved with all aspects of commerce in the cannabis, food and agricultural and botanical markets access to accurate real-time answers to their most important question: have my plants or crops been contaminated with fungi, molds, viruses or mildew?

If you are a cannabis testing lab, contact us today at or call us at 800-641-5751 to learn why PathogenDx DNA-based testing is your best choice for microbial testing.




Topics: cannabis testing

Written by Milan Patel