How to read a lab report (COA) in five steps

A lab report — a Certificate of Analysis, or COA — is the document in which a lab records what it measured in a sample from one particular batch. It is the only way to check, without being a chemist, that the label tells the truth.

You read it in five steps, from the simplest to the most technical. The first two tell you whether the document belongs to your product; the last three tell you what is in it. The Lab reports page shows how we handle the report for every batch.

Find the batch number on the report and compare it with the one printed on the bottle or box. It must be identical. A report “for the product” in general, with no batch, proves nothing about the bottle in your hand.

Then look at the test date: it should be close to the batch's production date. A report several years old next to a fresh product almost certainly belongs to another batch.

If the batch number does not match, the report is not for your product. Ask the shop for the report of the batch printed on the pack.

The report must show the lab's name and address, the method used — usually chromatography, HPLC or GC — and the signature of the person responsible for the results. A document without an identifiable lab is just a table.

It matters that the lab is independent of the maker and, ideally, accredited to ISO/IEC 17025 for the methods in question. In Romania accreditation is granted by RENAR, in other countries by the equivalent national body; the accreditation certificate number usually appears in the report's header.

The lab usually gives the result as a percentage or in mg/g, and the label as a percentage or in milligrams per bottle. 1 % means 10 mg/g, so a 10 % oil should show up on the report at around 100 mg/g.

A small difference is normal: the usual tolerance is ±10 %, so a 10 % oil is fine anywhere between 9 and 11 %. Besides CBD you will see other lines — CBDA, CBG, CBN, CBC. They show what kind of extract you have: in an isolate they are all not detected, in full spectrum small values appear. The article on full spectrum, broad spectrum and isolate explains the difference.

Look for the Δ9-THC (delta-9-THC) line and, if present, THCA — the acid form, which turns into THC when heated. Some labs also give a “total THC”, calculated as Δ9-THC + 0.877 × THCA. The best result is “ND” — not detected.

Cannabis and THC are controlled in Romania (Law 143/2000 and Law 339/2005), and the law sets no threshold for the finished product. The 0.3 % limit in EU rules concerns the plant in the field, not the oil. So for a product sold as THC-free, look for “ND” or “<LOQ”; for full spectrum, a small value written clearly as a number.

A complete report does not stop at cannabinoids. Hemp takes up what it finds in the soil, and extraction can leave traces of solvent, so the lab also looks for contaminants. Each line has a measured value and the limit it was compared against.

The limits depend on the product's regime. For food, the EU ceilings for contaminants and pesticide residues apply; in cosmetics heavy metals are prohibited substances, and technically unavoidable traces are tolerated only if the product stays safe (Regulation (EC) No 1223/2009, Art. 17).

• Heavy metals — lead, cadmium, mercury, arsenic.
• Pesticide residues.
• Residual solvents from extraction, for example ethanol.
• Microbiology and mycotoxins — especially for food products.

Reports are usually in English. Here is what the most common abbreviations mean.