Convalence Labs · Laboratory Notes
What Is a Certificate of Analysis (CoA) and How Can You Verify It?
14 September 2026
A Certificate of Analysis, commonly referred to as a CoA, is a document used to report the results obtained when a particular material or batch is tested against defined specifications.
CoAs are widely used across laboratories, manufacturers, suppliers and quality-control environments. They may accompany many different types of materials, including active pharmaceutical ingredients, chemical compounds, research materials and other products that require analytical testing.
A CoA can provide valuable information about a material, but it is important to understand what the document actually demonstrates and what it does not.
What Is a Certificate of Analysis?
A CoA is essentially a record of analytical testing performed on a specific sample or batch.
According to World Health Organization guidance, a certificate of analysis should identify the material that was tested, the relevant batch, the specifications and methods used, the results obtained and the date of testing. The document should also allow the results to be related to the laboratory or organization responsible for the analysis.
The exact format can vary between laboratories and industries, but the purpose remains similar: to provide documented evidence of the analytical results obtained for a particular material.
What Information Should a CoA Contain?
A properly prepared CoA should contain enough information to identify both the material and the testing performed.
Important details may include the product or material name, batch or lot number, specifications, analytical methods, individual test results, date of testing, and information identifying the laboratory or organization that performed the analysis.
The batch or lot number is particularly important because it provides traceability. A result reported for one batch should not automatically be assumed to apply to another batch.
The WHO describes the batch number as a distinctive combination of numbers or letters used to uniquely identify a batch on labels, batch records and corresponding certificates of analysis.
Specifications and Results Are Not the Same Thing
One of the most important points when reading a CoA is understanding the difference between a specification and a test result.
A specification defines the required acceptance criteria. The result shows what was actually obtained during the analysis.
For example, a document may specify a minimum purity requirement. That specification tells us the acceptance limit, while the analytical result tells us the value measured for the tested sample.
A useful CoA should therefore provide enough information to distinguish between what was required and what was actually observed.
Which Analytical Methods May Be Used?
The analytical methods listed on a CoA depend on the material and the characteristics that need to be evaluated.
Depending on the application, methods may include HPLC or UHPLC, gas chromatography (GC), mass spectrometry (MS), nuclear magnetic resonance (NMR), spectroscopic techniques, elemental analysis or other validated analytical procedures.
Each technique provides different information.
Chromatographic methods can be used to separate components and assess purity or related substances. Mass spectrometry can provide information about molecular mass and identity. Other techniques may provide complementary information about molecular structure or physical and chemical properties.
The choice of method should therefore be considered in relation to the analytical question being addressed.
Does a CoA Prove That a Product Is Authentic?
Not by itself.
A CoA is evidence of reported analytical testing. It does not automatically prove that the document is genuine, that it belongs to the material in your possession, or that the material has the same composition as the sample originally tested.
This distinction is particularly important when documents can be copied, modified or presented independently of the original laboratory.
For this reason, a CoA should be considered together with traceability, document verification and, when necessary, independent analytical testing.
How Can You Verify a CoA? https://convalencelabs.com/verify
A reliable laboratory should have a clear way of establishing that its analytical documents are genuine and traceable.
One useful approach is an official CoA verification system. This may take the form of a dedicated verification page on the laboratory's website, a unique certificate number, a QR code linked to the laboratory's official system, or another traceable mechanism.
The important point is not simply the presence of a QR code, logo or digital signature. These elements can potentially be copied.
Verification should ideally be performed through the laboratory's official website or verification system, rather than through contact details supplied only within the document.
Convalence Labs · Independent Analytical Testing