Hemp Lab Report Units Explained: Milligrams, Percent, PPM, ND, LOD and LOQ

Quick Answer: What the Units on a Hemp Lab Report Mean

A hemp certificate of analysis, or COA, uses a handful of unit types: milligrams (mg) for a dose, percent (%) or milligrams per gram (mg/g) for concentration, and parts per million (ppm) for very small trace amounts, usually contaminants. You will also see “ND,” “LOD,” and “LOQ” printed next to contaminant results. These three abbreviations tell you whether a compound was found at all, and if it was, whether the lab’s equipment could measure it precisely. Knowing what each one means helps you read the report correctly, but a lab report by itself does not confirm a product is safe, legal in your state, or right for you.

Why Hemp Lab Reports Use So Many Different Units

Hemp and cannabinoid testing is not standardized the way nutrition labels are. Different labs, different states, and different testing panels can each format results differently. A cannabinoid potency section usually reports a concentration, while a contaminant panel usually reports a pass or fail against a very small threshold. These are different kinds of measurements, so they use different units.

Government-backed measurement science groups have been working to make cannabis and hemp lab testing more comparable across laboratories. The National Institute of Standards and Technology runs a Cannabis Laboratory Quality Assurance Program that helps testing labs verify their methods against a shared reference and produces hemp reference materials that labs can use to calibrate their equipment. This kind of program exists specifically because measurement comparability between labs has been a real challenge in this industry.

The Core Units You Will See on a Cannabinoid Panel

• mg (milligram): A dose amount, usually per gummy, per serving, or per container. This is the unit most shoppers compare on labels.
• mg/g (milligrams per gram): Concentration by weight, common for raw plant material or concentrates rather than finished gummies.
• % (percent): Concentration by weight, another way of expressing mg/g. Often used for total THC and total CBD lines, especially near compliance thresholds.
• ppm (parts per million): A very small trace amount, most often used for contaminants such as pesticides, heavy metals, and residual solvents.

A percent and a milligram-per-gram figure describe the same kind of thing, concentration, just expressed differently. Neither one tells you the milligram dose of a single gummy unless you also know the gummy’s weight. This is one reason a hemp gummy label and its matching COA do not always show the same number style side by side.

ND, LOD, and LOQ: The Three Abbreviations That Confuse Most Readers

These three terms appear most often on contaminant panels, such as those for pesticides, heavy metals, or residual solvents.

• ND (Not Detected): The lab’s test did not find the substance in the sample, or found it at a level too low for the equipment to confirm.
• LOD (Limit of Detection): The smallest amount of a substance the lab’s equipment can reliably tell apart from background noise. Below this level, the lab cannot confidently say whether the substance is present at all.
• LOQ (Limit of Quantitation): The smallest amount the lab’s equipment can measure accurately enough to report as a specific number. A substance can be detected above the LOD but still fall below the LOQ, meaning the lab knows something is there but cannot state a precise amount.

In practical terms: ND is a result, while LOD and LOQ are the sensitivity thresholds behind that result. A report that says “ND” for lead means the lab looked and found nothing above its detection threshold, not that zero lead exists in an absolute sense. This is a standard and expected way for a laboratory report to describe measurement limits, not a sign of a problem with the product.

Worked Example: A Fictional Label Next to a Fictional COA

The numbers below are invented only to show how the math and units connect. They do not describe any real product.

• Label claim: “25 mg CBD per gummy,” container holds 20 gummies.
• COA potency section: Reports CBD as “1.1%” for the tested batch, along with a total gummy weight of roughly 2.3 grams per piece.
• Doing the conversion: 1.1% of 2,300 mg (2.3 grams) is about 25 mg. That lines up with the label claim.
• COA contaminant section: Lead is listed as “ND (LOD 0.05 ppm, LOQ 0.10 ppm).” This means the lab’s equipment could reliably detect lead down to 0.05 ppm and precisely quantify it down to 0.10 ppm, with no lead detected above that.

This example shows the kind of cross-check a shopper can do: convert the COA’s percent or mg/g figure using the product’s actual weight, then compare it to the milligram number on the label. If the math is close, the batch-tested result and the label claim are consistent. If it is far off, or if the batch number on the COA does not match the package, that is a gap worth noting before relying on either number.

Checklist: Reading the Units Section of a COA

1. Confirm the report shows a batch or lot number that matches the package in hand, not a generic product-line report.
2. Check whether cannabinoid potency is listed in mg, mg/g, or percent, and convert it to a per-gummy or per-serving milligram figure if the label uses milligrams.
3. Look at the contaminant panels for ND and note the LOD and LOQ values listed next to each substance, if the lab provides them.
4. Check the report date. An old report on a current package is a gap worth noting.
5. Identify which cannabinoid is being measured. CBD, total THC, Delta-9 THC, and THCA are not interchangeable figures.
6. Remember that a COA describes the sample tested, not a guarantee about every unit in the container.

Limits of What a COA’s Units Can Tell You

• A COA reflects one tested sample from one batch. It does not certify every gummy in every container as identical.
• An “ND” result depends on the lab’s detection and quantitation limits. A different lab with different equipment could report a different LOD or LOQ for the same substance.
• Percent and mg/g figures require a known product weight to convert into a per-gummy dose. Without that weight, the conversion is only an estimate.
• A units section cannot confirm legality in your state, FDA approval, or personal safety. Those are separate questions from what the lab measured.
• This guide does not evaluate or confirm the accuracy of any specific product’s actual lab results. Only the batch-matched COA for the product you are holding can do that.

Who Should Be Extra Cautious

• Anyone who is pregnant or breastfeeding. The FDA has advised against CBD, THC, or marijuana use in any form during pregnancy or while breastfeeding, citing unanswered safety questions.
• Anyone taking prescription medication, since cannabinoids can affect how other drugs are processed and may increase the risk of side effects.
• Anyone subject to workplace, military, sport, or legal drug testing, since even hemp-derived products can carry detectable cannabinoid levels.
• Parents storing any hemp product in a household with children, since accidental ingestion of THC-containing food products by children has been a documented safety concern.

Frequently Asked Questions

Why does a COA sometimes show a percent instead of a milligram figure?

Percent and milligrams per gram both describe concentration, which is common for testing raw material, oil, or bulk batches before they’re divided into individual gummies. You need the product’s actual weight to convert a percent figure into a per-gummy milligram dose.

Does “ND” mean a contaminant is completely absent?

Not necessarily in an absolute sense. “ND” means the lab did not detect the substance above its limit of detection (LOD). Extremely small amounts below that threshold could theoretically be present without being measurable by that specific test.

If a substance is “detected” but below the LOQ, is that a safety problem?

A result between the LOD and LOQ means the lab detected a trace of the substance but cannot provide a precise, reliable value. This is a measurement limitation, not by itself a statement about health risk. This article does not evaluate what any specific level means for safety; a qualified professional can speak to that.

Does a batch-matched COA prove a product is legal and FDA-approved?

No. A COA confirms lab-tested results for one submitted sample. The FDA has stated that, other than one prescription CBD drug product, it has not approved CBD products, and that CBD products remain illegal to market as an added food ingredient or dietary supplement under federal law. Check current federal and state requirements separately from any lab report.

Related Reading

For help matching the milligram numbers on a hemp gummy package to its serving size and container total, see our guide to reading gummy, serving, and container milligram labels. For more on how this site researches and sources its label and lab-report content, see our editorial standards and editorial team and review process pages.

Educational Disclaimer

This article is general consumer education about reading units and abbreviations on hemp and cannabinoid lab reports. It is not medical, legal, or dosing advice, and it does not evaluate, endorse, or confirm the content, purity, legality, or effects of any specific real product. Hemp and cannabinoid laws change and vary by state; confirm current requirements before buying, possessing, shipping, or using any product. For personal health questions, consult a qualified healthcare provider. See our medical disclaimer for more.