Testing & Product Quality
What COAs, identity testing, purity assays, sterility testing and product traceability can and cannot establish.
A Certificate of Analysis can document specific tests on a specific sample or lot. It does not turn one test result into proof of every quality attribute, and it does not establish clinical safety or effectiveness.
What common tests actually answer
| Quality question | What it addresses | What it does not prove by itself |
|---|---|---|
| Identity | Whether the tested material is consistent with the claimed molecular identity using an appropriate, specific method. | How much active material is present, sterility, stability or clinical effect. |
| Purity / chromatographic profile | The relative chromatographic components detected under the stated method. | Identity from one nonspecific retention result, absolute content, sterility or endotoxin status. |
| Assay / content | How much analyte is present against a defined method/reference basis. | That impurities are absent or that the material is sterile and clinically suitable. |
| Sterility / microbiology | Whether the tested product meets the stated microbiological acceptance criteria. | Identity, potency, efficacy or long-term stability. |
| Endotoxin / pyrogen testing | A separate assessment relevant to pyrogenic contamination risk where applicable. | Sterility, molecular identity or clinical effectiveness. |
| Stability | Whether specified attributes remain within criteria over defined time, formulation, container and storage conditions. | A universal storage life for other containers, formulations or handling histories. |
Why “99% purity” is not the whole answer
Drug-quality specifications normally treat identity, assay/content, purity/impurities and — for sterile products — sterility, endotoxins/pyrogens and particulate matter as separate attributes. A single HPLC percentage therefore cannot substitute for the rest of the quality profile.
COA checklist
Review traceability, test methods and missing fields.
Open checklist →Identity registry
Keep molecule, salt, fragment, formulation and market nickname separate.
Identity →Storage & handling
Understand why formulation state changes stability assumptions.
Storage →Safety unknowns
Product-quality uncertainty adds to, rather than replaces, biological safety uncertainty.
Safety →