What information does a COA contain?

What a COA is

A certificate of analysis (COA) is a document issued by a laboratory that reports the results of tests carried out on a sample from a specific lot.

Data that identify the sample

The first step is to check that the document matches the product you are looking at:

• Laboratory issuing the report.
• Compound name and declared presentation (for example, 10 mg).
• Lot number.
• Date of analysis or issue.
• Sample or report identifier.

What the most common tests measure

High-performance liquid chromatography (HPLC) separates the components of the sample and is commonly used to estimate purity, expressed as a percentage.

Mass spectrometry (MS) measures the mass of molecules and is used to check identity: that the observed mass matches the one expected for that compound.

Depending on what was requested, a COA may include other tests, such as content per vial, moisture or endotoxins. If a test does not appear in the document, it was not performed or not reported.

What it does not prove

A COA is valuable information, but its scope is specific:

• It describes the sample tested; on its own it does not guarantee other lots.
• Purity is not quantity: a vial can have high purity and a content different from the one declared.
• Each method detects certain impurities and may miss others.
• It is not a health authorisation or an instruction for use.
• Its reliability depends on the issuing laboratory; ISO/IEC 17025 sets competence requirements for testing laboratories.

How they are shown at BESTLA

The certificate library shows, when they appear in the document, the laboratory, lot, date and declared presentation. If a certificate corresponds to a presentation different from the product's, the library says so explicitly.