A certificate of analysis, or COA, reports test results for a sample. It is useful evidence when the sample, method, and result can be traced. It is not a complete assessment of a product’s clinical safety, and a clean-looking report cannot answer questions it never tested.
Begin with the sample, not the percentage
Record the sample identifier, lot number, laboratory, report date, and description of the material received. Ask how that sample relates to the product being discussed. A document may be authentic yet concern a different lot or a sample selected by someone with a financial interest in the result.
A chain of custody records who handled the sample. It helps establish traceability, but it does not make one sample representative of every item a supplier sells. Keep the scope of the claim tied to the scope of the testing.
Separate the questions the tests answer
Identity asks what the material is. An assay measures the amount of the specified substance. Impurity testing looks for other constituents within the scope of the method. Microbiological testing addresses a different set of questions.
FDA’s quality-testing programme lists these as distinct test categories. Its approach also uses inspections and other quality information alongside sample analysis.
Sources: U.S. FDA
Why purity does not establish sterility
A purity result and a sterility result are not interchangeable. A chemical analysis cannot be assumed to have tested for viable microorganisms or bacterial endotoxins. Look for the specific methods and acceptance criteria rather than inferring them from a high percentage.
FDA’s manufacturing guidance treats sterile-product quality as a matter of facilities, process controls, and testing through the product’s shelf life. One final test is only part of that system.
Sources: U.S. FDA
Read the limitations box
Check the units, reference standard, detection or quantification limits where relevant, and whether the test was quantitative. “Not detected” is meaningful only in the context of the analyte and the method’s capability. An untested impurity should not be described as absent.
Do not convert an area-percentage purity result into a claim about milligrams in a vial without an appropriate quantitative assay. That is a different measurement, and the report needs to support it explicitly.
Use a report review checklist
- Does the sample identifier match the lot being discussed?
- Can the laboratory verify the report through its own contact details?
- What exactly was measured, using which method and units?
- Which quality questions were outside the testing scope?
- Does the conclusion claim more than the results establish?
Use this checklist to interpret evidence, not to certify a research product for self-administration. Clinical suitability and a product’s lawful medical supply pathway are separate questions.
Conclusion
A useful COA has a traceable sample and clearly defined tests. Read it as a bounded laboratory result, not a universal guarantee about safety, efficacy, or the supplier.