“THC: Non-Detect” is the most reassuring line on a certificate of analysis and one of the least informative.
Non-detect means the laboratory did not find the compound. It says nothing about whether the laboratory could have found it. Those are different claims, and only one of them helps you make a sourcing decision.
LOD and LOQ
Two values determine what a non-detect result actually means.
Limit of detection (LOD) is the lowest concentration the method can reliably distinguish from zero.
Limit of quantitation (LOQ) is the lowest concentration the method can reliably measure as a number.
“ND” means: below the limit of detection, for this method, on this instrument, at this laboratory. Change any of those variables and the result can change.
Why a Clean COA Can Still Fail Customs
Consider a certificate reporting THC as non-detect with a detection limit of 0.05%. That is 500 parts per million.
The material could contain anywhere from zero to just under 500 ppm and still produce a non-detect result.
If you are selling into a market with a 1 ppm threshold, that certificate tells you nothing useful. The detection limit sits 500 times above the limit you need to clear.
The material might be entirely compliant. The document simply cannot demonstrate it.
This is not a hypothetical failure mode. Products are held at customs on exactly this basis: an accurate certificate, honestly produced, that was never capable of answering the question being asked of it.
HPLC and LC-MS/MS
Different analytical methods have different sensitivity.
HPLC (high-performance liquid chromatography) is the standard method for cannabinoid potency testing. It is accurate and appropriate for percentage-level measurement. Its detection limits are generally not designed for trace-level work.
LC-MS/MS (liquid chromatography with tandem mass spectrometry) is built for trace analysis. Mass spectrometry detection reaches substantially lower concentrations, which is what trace-level thresholds require.
Neither method is better in the abstract. They are built for different jobs. A method appropriate for confirming 99% purity is not necessarily appropriate for confirming sub-1 ppm THC content.
The problem is not using HPLC. The problem is using an HPLC result to answer a question the method was not designed to answer.
Three Questions to Ask About Any COA
Ask these of every supplier, including the ones you trust:
- What analytical method was used?
- What is the limit of detection for THC under that method?
- Is that detection limit below the threshold I need to meet?
If the answer to the third question is no, you do not have compliance documentation. You have a document that is silent on your question.
If a supplier cannot answer these quickly, that is itself informative. Every accredited laboratory reports detection limits. If they are absent from a certificate, they were either removed or the certificate is abbreviated.
Matching Method to Threshold
A lower detection limit is not automatically better for every purpose.
Trace-level methods cost more, take longer, and can be more sensitive to matrix effects. If you are selling domestically against a percentage-level threshold, a standard HPLC panel is the correct tool and you should not pay for more.
The principle is simply to match the method to the threshold:
- Percentage-level domestic compliance → standard HPLC panel is appropriate
- Sub-ppm export thresholds (Japan, for example) → trace-capable methodology required
Specify what you need before ordering rather than discovering a gap during a regulatory review.
Frequently Asked Questions
What does “non-detect” mean on a cannabinoid COA? It means the laboratory did not detect the compound at that method’s limit of detection. It is a statement about the method’s sensitivity as much as about the material.
Is non-detect the same as zero? No. Non-detect means below the detection threshold of the test used. The material may contain the compound at a concentration the method cannot resolve.
What detection limit do I need? Lower than the regulatory threshold applicable to your product and market. If your market’s limit is 1 ppm, a method with a 0.05% detection limit cannot demonstrate compliance.
Why don’t all labs report the same way? Laboratories use different instrumentation and methods, with different sensitivities. Both can be accurate and produce different results from the same sample. This is why methods and limits must be stated alongside results.
Should I always request the most sensitive testing available? Not necessarily. Trace methods cost more and are not required for percentage-level thresholds. Match the method to the market you serve.
Want to see how our certificates present methods and detection limits? Request a recent COA for any material. Contact sales@cannvital.com.
Cannvital is a bulk cannabinoid manufacturer in Las Vegas, Nevada. All materials are tested by ISO 17025-accredited third-party laboratories. cGMP certified under 21 CFR Part 117, 210, 211, FDA-registered, Halal, Kosher and USDA hemp certified.