LOD vs LOQ: What Non-Detectable THC Means on a CBD COA

Short answer: LOD is the limit for detecting a substance; LOQ is the limit for measuring its amount reliably. Neither proves absolute zero. To interpret “ND” or “<LOQ” for THC, read the laboratory’s own legend, units and reporting threshold on the batch certificate of analysis (COA).

What is the difference between LOD and LOQ?

The NIST definition of limit of detection concerns distinguishing a substance from a blank sample. Its definition of quantitation limit concerns measuring an amount with acceptable accuracy and precision. Detecting a signal and reporting a reliable number are different tasks.

Term	Question it answers	Limit of the conclusion
LOD: limit of detection	Can this method distinguish the substance from background?	A result below the limit does not establish absence.
LOQ: limit of quantitation	Can this method measure the amount reliably?	A result below the limit is not a measured zero.
Reporting limit	What threshold does this laboratory use when reporting this result?	Read its definition; do not assume it always equals LOD or LOQ.

Does ND mean the same thing as <LOQ?

No universal interpretation should replace the report legend. ND commonly means “not detected” at the laboratory’s stated reporting threshold. “<LOQ” means below the quantitation limit; that notation alone does not tell you whether the lab detected a signal. A result explicitly marked “detected, below LOQ” is different from a non-detect result.

Ask the laboratory to explain an undefined code. Check the limit for each reported THC compound; a delta-9 THC result alone does not describe every other cannabinoid. A rounded “0.0%” on packaging is also not a substitute for the laboratory’s result.

Worked example: 0.01% THC LOQ in mg/g

Illustrative numbers only: suppose a report gives a THC LOQ of 0.01% by weight and a result of <LOQ. The conversion is:

0.01% w/w × 10 = 0.1 mg/g.

That converts the quantitation boundary, not the sample’s measured THC concentration. The report has not measured 0.1 mg/g, and it has not established zero. Do not present that boundary as an actual amount consumed or a drug-test prediction.

Percent by weight converts to mg/g. Converting mg/g into mg/mL additionally requires the product’s density; do not silently assume one gram equals one milliliter. See the complete worked COA example for batch, CBD potency and missing-panel checks.

Can you compare two ND reports?

Record the compound, result code, limit, units, product type and method from each report. Compare equivalent units and read both legends. A smaller numerical threshold describes a lower reporting boundary only when those details are comparable. It is not a rating of overall product quality.

If either report omits the threshold or uses a different meaning for ND, ask for clarification instead of ranking the products by the letters “ND.” Use our seven-step COA checklist.

Can a low THC LOQ guarantee a negative drug test?

No. A product COA and a test of a person’s biological sample answer different questions. A product concentration in mg/g cannot be compared directly with a urine concentration in ng/mL to predict a result.

For U.S. Department of Transportation testing, CBD use is not a legitimate medical explanation for a confirmed marijuana-positive result. Read the DOT CBD notice and our drug-testing guide. This DOT rule should not be assumed to describe every employer or country.

What should you request when a lab report is incomplete?

The full report for the exact product and batch.
The meaning of ND and any qualifiers beside the result.
The applicable THC reporting limits and units.
The method and laboratory identity.
Any contaminant panels the seller says were performed.

A missing result is an unanswered question. A spectrum label or seller assurance cannot fill in missing measurements.

Updated October 23, 2026. General education, not individual medical, legal or employment advice. See our editorial standards and commercial disclosure. Send a correction.