“Tested” means little unless the test is specified. A report may describe chromatographic purity while leaving other properties entirely unexamined. At least four questions should be distinguished to make the results understandable.
1. Chromatographic purity
A purity value from an HPLC/UV analysis describes the ratio of evaluated peak areas under the measurement conditions used. It is not universal proof that every unwanted substance is absent. The method and its separation performance are part of the interpretation.
2. Identity
Identity concerns whether the properties analysed match the expected peptide. Mass spectrometry can support this assessment. A report should show which properties were actually tested; a matching mass does not automatically answer every structural question.
3. Bacterial endotoxins
Endotoxins are examined using dedicated procedures, such as an appropriate LAL test. The FDA treats this separately from other quality tests and stresses that the method must be suitable for the particular sample. An endotoxin result does not demonstrate sterility or automatically cover every possible pyrogen. Units and methodological limitations must accompany the result; general limits cannot be applied to every research setting.
4. Elemental impurities
ICP-MS can be used to examine selected elements. Agilent, for example, demonstrates the determination of several elemental impurities in pharmaceutical starting materials. Such a test addresses only the elements explicitly analysed. It does not replace peptide identification or microbiological testing. Sample preparation, units and limits of quantification also matter.
Compare reports side by side rather than mixing different figures
A useful assessment gives each property its own row: sample examined, method, result, unit and limits of interpretation. If a test is missing, the field is marked “not established”. A good result in another row does not fill this gap.
Frequently asked question: Does “passed” automatically mean safe?
No. Without the test criterion, it is unclear what was passed. Even several laboratory results do not constitute general approval for human use. This overview explains analytical evidence for research and laboratory settings.
Further reading: Endotoxins and the LAL test. The laboratory overview provides access to published reports. Check the specific scope of each report and its link to the batch.