KNOWLEDGE CENTER · Laboratory Quality
How to Read a Peptide Certificate of Analysis
A field-by-field COA checklist for matching a report to a research lot, interpreting its results and identifying what remains unknown.
Published by THAI BIO LABSSelected sources checked: · AI-assisted screening; specialist review pending
Article contents
CORE ANSWER
A certificate of analysis (COA) records tests and reported results for a material or sample. Read it in this order: identify the material and lot, establish who issued the report, inspect the methods and results, then verify its source and limits. A percentage by itself cannot answer all of those questions.
Match the report to the material first
Compare the product name, stated form, lot identifier and sample code with the material you are evaluating. If the laboratory used its own sample identifier, look for an explicit link to the supplier’s lot. Do not assume that a report for a similar name or previous lot applies.
ICH Q7 addresses representative sampling in section 7.3 and certificate information in section 11.4. A matching lot code does not establish how a sample was selected. This API manufacturing guidance is a reference for reading documentation, not a claim of TBL GMP certification. [1]
COA fields: what to read and what to check
Use this checklist alongside the original report. Report formats vary: an absent field is a question to resolve, not automatic proof of an invalid document. The checks below are TBL editorial guidance, not a certification scheme.
On small screens, scroll the table horizontally to read every column. With the table focused, use the arrow keys.
| Field | What it tells you | What to check or avoid inferring |
|---|---|---|
| Material name and form | Which material the report describes. | Match the product name and stated form. Ask about unexplained abbreviations or differences. |
| Lot and sample identifiers | The link between the submitted sample and the supplied lot. | Look for a documented mapping when the laboratory sample code differs from the vial lot. A matching code alone is not authentication. |
| Issuer, laboratory and commissioning party | Who issued the document, who tested the sample and who requested the work. | Keep manufacturer documents and separately commissioned reports identifiable. A logo alone does not explain these roles. |
| Report identifier and dates | Which report version and testing period you are reviewing. | Distinguish sampling, testing and issue dates where shown. Ask whether a corrected report supersedes the copy you have. |
| Method and analytical scope | What each test was designed to examine. | Read the method alongside the result; the instrument name alone is not a complete method or validation record. |
| Identity result | The reported evidence supporting the named material. | Check which identification method was used and what conclusion the laboratory actually states. |
| Purity result | The reported purity on the stated analytical basis. | Keep chromatographic area percentage separate from mass per vial. Do not add an unreported content value. |
| Content or assay, with units | A reported quantitative result, if this test was performed. | Check the units and basis. A declared vial amount and a measured content result are different records. |
| Acceptance criteria and outcome | How the result compares with a stated specification. | Separate the acceptance limit from the measured value. A pass label without its scope does not answer every quality question. |
| Additional tests | Only the extra tests actually included in this report. | If water, residual solvents, endotoxin or sterility results are absent, mark them as not reported; do not infer a pass. |
| Storage, retest or expiry information | The conditions or dates stated for the material, when included. | Use the documented terms. Do not calculate a shelf life from a purity result or substitute a generic guide. |
| Verification route and source file | A way to locate the issuing source or original report. | Check the destination and report identifier. A working QR code or portal link is not proof of representative sampling or suitability. |
Keep identity, purity and content separate
Identity asks which material is present. Purity describes the result on the stated analytical basis. Content or assay measures an amount using a suitable quantitative procedure. A report can cover one of these without covering all three.
ICH Q2(R2) treats identification, assay and impurity testing according to their intended purpose. Selectivity, accuracy and the relationship between response and amount matter to interpretation; an instrument label does not replace these method characteristics. [2]
Read a chromatographic percentage as the reported chromatographic measurement. Do not turn it into milligrams per vial. For a blend, check whether the document identifies and quantifies individual components or only reports an overall result.
Missing, not detected and zero are different
- Not reported: this copy provides no result for the parameter. Do not infer that the test passed or failed.
- Not tested: the document explicitly states that the test was not performed.
- Not detected or below a limit: read the stated detection or quantitation limit, method and units; this is not the same statement as zero.
- Pending: the result or document is not yet available. It is not a completed test outcome.
Ask the issuer to explain unclear terminology. If a required result is missing, record that limitation in your evaluation instead of substituting a result from another lot.
Verify the source and preserve the report version
Where a laboratory provides a verification service, check that the link reaches the intended issuer and that the report identifier and contents match. If no public service exists, use the issuer’s published contact route to ask about verification. A missing portal alone does not prove that a report is false.
Keep the complete source file, its date or version, and the lot mapping. A QR code that opens a page establishes only that the link works. It does not establish who collected the sample, whether that sample represents the batch or whether the material is suitable for a particular experiment.
If the source copy, lot mapping or results disagree, seek clarification and retain both versions. Do not silently repair the discrepancy in your own record.
Use a COA with TBL Batch Records
Batch Records provide the place to connect a published lot with its available documentation. Distinguish the record’s publication or release status from the individual results, and keep manufacturer documentation distinguishable from separately commissioned testing.
Before TBL’s initial peptide purchase and testing cycle, there are no current lot records to match. This guide explains the checks to make when real records are available; it does not present a sample certificate as a completed TBL result.
A COA does not by itself establish sterility, safety for human use, regulatory approval or clinical effectiveness. Use it for the analytical questions it actually addresses.
KEY PRINCIPLE
A useful COA connects a defined sample to identifiable testing and a traceable source. Preserve both what the report establishes and what it leaves unanswered.
TECHNICAL REFERENCES
Standards and source material
Numbered markers link specific technical statements to the sources below. Other practical guidance is TBL editorial interpretation. These references do not certify a TBL lot, method or shelf life.
Batch Records
Match a COA to its published lot
Search THAI BIO LABS Batch Records by lot identifier to review the documentation associated with a released record.
Search Batch RecordsFor TBL vial specifications and current release status, compare the research-peptide catalogue and prices.
RESEARCH-USE BOUNDARY
For research use only. Not for human or veterinary use.
THAI BIO LABS Knowledge Center content explains scientific terminology, analytical methods, documentation and laboratory-handling concepts. It does not provide medical advice, treatment protocols, dosing or administration instructions.
