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Testing Notes: COAs May Show “ND” (Non‑Detect) for Some Terpenes or Analytes

“ND” on a certificate of analysis (COA) does not mean the compound is absolutely absent. It means the lab’s method could not detect it at or above a defined threshold. This page explains how to read ND results conservatively and practically—whether for terpenes, THC, residual solvents, pesticides, heavy metals, or microbes.

What “ND” means on a COA

ND (non‑detect) indicates the analyte was below the method’s detection capability—not necessarily zero. Two key limits frame this:

  • LOD (Limit of Detection): The lowest level that can be reliably distinguished from noise. Below this, the lab reports ND.
  • LOQ (Limit of Quantitation): The lowest level that can be measured with acceptable precision and accuracy. Results between LOD and LOQ may appear as “trace,” “DET,” or “<LOQ.”

Different labs, instruments, and methods use different LOD/LOQ values. Analyte‑specific method details matter.

Why a result can be ND

  • Method and instrument: GC‑MS vs LC‑MS vs HPLC, targeted vs broad panels, and run parameters change sensitivity.
  • Sample preparation: Dilution factors, extraction efficiency, and matrix cleanup can push a low level below LOD.
  • Matrix effects: Oils, gummies, and topicals behave differently; interference can mask signals.
  • Analyte properties: Volatile terpenes can evaporate; heat‑sensitive compounds can degrade; metals and pesticides require different chemistries.
  • Stability and storage: Time, heat, light, and oxygen can reduce terpene or cannabinoid levels between production and testing.

Interpreting ND by analyte type

1) Terpenes

  • ND is common in CBD isolate products: Isolate has most non‑cannabinoid compounds removed. If terpenes are not added back, many or all will be ND.
  • Broad‑spectrum or “terpene‑infused” claims: If a label claims terpene content but the terpene panel shows ND for all targets, ask about (a) which terpenes were added, (b) their expected levels, and (c) the panel’s LODs.
  • Panel coverage: Terpene panels test a finite list. A terpene not on the list will read as ND even if other terpenes are present.
  • Loss over time: Terpenes are volatile; storage and heat can drop levels below LOD, yielding ND.

2) THC and other cannabinoids

  • ND ≠ zero THC: It means THC is below the method’s LOD. For “THC‑free” or “non‑detectable THC” claims, review the THC LOD/LOQ and the detection method. See Non‑Detectable THC Claims: How to Verify.
  • Cross‑lab differences: One lab may report ND while another detects a trace if the second lab’s LOD is lower.
  • CBDA/CBD conversions: Decarboxylation during processing can change profiles; use total cannabinoid calculations and consistent units. See COA Units & Conversions.

3) Contaminants (pesticides, residual solvents, heavy metals, microbes)

  • ND is generally a good sign for safety panels, provided the method’s LOD/LOQ is at or below the applicable limit (regulatory, pharmacopeial, or internal spec).
  • “Pass” without numbers: Prefer COAs that list each analyte’s result and the panel’s action limits—not just “Pass/Fail.”
  • Units and matrices matter: Compare gummies (mg/kg or ppm) vs oils (mg/kg or mg/g) appropriately; check that sample prep and moisture corrections are stated. See COA Units & Conversions.

Practical steps to verify ND

  1. Find the LOD/LOQ on the COA: Look for a footnote or column listing LOD/LOQ per analyte. If missing, request it from the brand or lab.
  2. Check the method: Identify technique (e.g., HPLC‑UV for cannabinoids, GC‑MS for terpenes/solvents, ICP‑MS for metals) and whether it’s validated for that matrix.
  3. Confirm units and basis: mg/g, mg/mL, ppm, or %; as‑is vs dry weight; dilution factors. Convert before comparing across products.
  4. Match identifiers: Batch/lot number, product name, and sample date should match the product in hand. See How to Read a Pet CBD COA (applies to human products too).
  5. Ask about panel coverage: If a claimed terpene isn’t in the lab’s target list, request a panel that includes it or a formulation spec.
  6. For “THC‑free” products: Verify a sufficiently low THC LOD/LOQ and method suitability. See Verify Non‑Detectable THC Claims.

Common scenarios

Scenario A: CBD isolate oil, no added terpenes

Terpene panel shows ND across most or all targets. This is expected and not a quality issue by itself. Cannabinoid panel should show CBD as the dominant analyte, with THC reported ND (or very low) depending on method sensitivity.

Scenario B: Broad‑spectrum label claims “terpene‑rich”

If the terpene panel shows ND for all targets, request the claimed terpene list, target potencies, and the panel’s LODs. A third‑party flavor (natural/artificial) does not guarantee measurable terpene content. See Terpenes Guide.

Scenario C: Residual solvent ND

ND is favorable, but confirm the method’s LOD is below the limit for your market and matrix, and that the tested solvent list matches the extraction/process used.

Scenario D: Heavy metals ND

Good outcome, but ensure the lab used ICP‑MS or equivalent with appropriate LOD/LOQ for Pb, Cd, Hg, As in the specific matrix (oil vs edible). Batch‑level consistency matters.

Scenario E: Two labs, different results

Lab 1: ND. Lab 2: detects a trace. Often explained by different LOD/LOQ, sample prep, or matrix effects—not necessarily a formulation change.

Red flags to watch for

  • “Pass” with no raw numbers, no LOD/LOQ, no method.
  • Mismatched batch or product name between label and COA.
  • Terpene‑rich claims but ND across the entire terpene panel without an explanation or formulation spec.
  • Only a QR code to a marketing page instead of a lab‑issued PDF with signatures and dates. See How to Spot Fake THC‑Free CBD.
  • Inconsistent units (% on label vs mg/mL on COA) without conversion. See COA Units & Conversions.

FAQs

Does ND mean zero?

No. ND means the analyte is below the method’s LOD. There could still be an amount present under that threshold.

Why would one lab find a trace while another reports ND?

Different LOD/LOQ, instruments, sample prep, or matrix effects. A method with a lower LOD can detect amounts another lab cannot.

Should I expect terpenes in THC‑free CBD isolate products?

Not unless they are added back. Many isolate‑based products will show ND for most terpenes, which is normal.

What ND level supports a “THC‑free” positioning?

There is no single global standard. Verify that THC LOD/LOQ is appropriately low for the claim and your market’s rules, and that the method is suitable. See Verify Non‑Detectable THC Claims and Labeling & Claims Compliance.

Is ND required for all contaminants to consider a batch safe?

Not always. Some methods can report low, quantified values that still meet safety limits. What matters is compliance with the applicable limits for the product and market.

This page is for general informational purposes. It does not replace lab documentation, regulatory guidance, or professional advice for your jurisdiction.