How to read a lab report: the COA guide for Switzerland

A Certificate of Analysis is the only document that proves the quality of a cannabis batch — and the one almost nobody knows how to read. This guide explains line by line which values matter, why "total THC" decides legality in Switzerland, and how to spot a worthless report.

At a glance

  • What counts is "total THC" (THC + converted THCA), not raw THC — in Switzerland it must stay below 1%.
  • A valid report names the lab, method, batch number and testing date. Missing any of those makes it unusable.
  • Four areas belong in a full report: cannabinoids, pesticides, heavy metals, microbiology.
  • Terpene analysis is optional but the best indicator of aroma and expected experience.
  • Most common red flag: a report with no batch reference, reused for the entire product range.

What a COA contains, line by line

Lab reports follow a fixed structure: a header with client, laboratory, sample name, batch number, receipt and testing dates. Then come the measurements, each with method and limit of quantification (LOQ). Values below that limit appear as "<LOQ" or "not detected" — a good result, not missing data.

Watch the units: cannabinoids are given in percent or mg/g (1% = 10 mg/g), pesticides and heavy metals in mg/kg or ppm. Confusing them makes a normal product look heavily contaminated, or the reverse.

Total THC: why the formula decides legality

In the fresh plant, THC exists almost entirely as its acid form THCA. Only heat — smoking, vaporising, baking — converts it into active THC. Labs therefore use the decarboxylation formula: total THC = THC + (THCA × 0.877), the factor reflecting the mass lost with the carboxyl group.

For Switzerland this is the decisive point: the total value must stay below 1%. A report showing 0.2% "THC" while omitting 1.4% THCA is in fact describing a product above the limit. The same logic applies to CBD: total CBD = CBD + (CBDA × 0.877).

Five red flags of a worthless report

Faked or misleading COAs are common in online retail. These five patterns show up most often.

  • No batch number — A report without a batch reference can be attached to any product and proves nothing.
  • Only a screenshot — Reputable labs issue a full PDF with signature, method and quantification limits.
  • Cannabinoids only — Without pesticides, heavy metals and microbiology the safety of the batch is not established.
  • Report predates the harvest — Testing and harvest dates must line up, otherwise the report belongs to a different batch.
  • Lab cannot be found — An accredited laboratory is verifiable. If it does not exist online, the report is unusable.

Terpenes in the report: the key to aroma and effect

Cannabinoids explain how strong a product is; terpenes explain how it feels. Terpene testing is optional and therefore a strong quality signal: it costs the producer money and is usually ordered only for good material.

Orientation: myrcene (earthy, calming), limonene (citrus, uplifting), caryophyllene (peppery, physical), pinene (pine, clear), linalool (floral, relaxing). Total terpene content above 1.5% is excellent for flower; below 0.5% the flower usually tastes and feels flat — a common sign of drying too hot or storing too long.

Frequently asked

What is a cannabis COA?
A Certificate of Analysis is the lab report for one specific batch. It documents cannabinoids, pesticides, heavy metals and microbiology with method, limit of quantification and testing date.
How is total THC calculated?
Total THC = THC + (THCA × 0.877). The factor accounts for mass lost during decarboxylation. In Switzerland this total must stay below 1%.
What does "<LOQ" mean on a lab report?
The value lies below the method's limit of quantification. For pesticides and heavy metals that is exactly the desired outcome.
Must every CBD batch be tested in Switzerland?
To sell legally you must be able to prove the product stays below 1% THC. Serious suppliers therefore test every batch and publish the report.
How do I spot a faked lab report?
No batch number, a screenshot instead of a PDF, cannabinoids only, a testing date before the harvest, or a laboratory that does not exist online.
How important are terpene values?
Irrelevant for safety, decisive for the experience. Above 1.5% total terpenes is excellent for flower; below 0.5% it usually tastes flat.

We sell only legal Swiss CBD products containing less than 1% THC, to people aged 18 or over. Prices shown come from our own price index and are not third-party offers. Not medical advice. Last updated August 2026.