A vial arrives. The label says one thing, the certificate says another. This is more common than most buyers expect, and the right response depends entirely on which field disagrees — some mismatches are clerical and resolve with an email, and one category should stop work until it is settled.
This covers how to triage a discrepancy, what to record before contacting anyone, and how to escalate. It is receiving and quality practice; the material is supplied for laboratory research only.
Record first, ask second
The instinct is to email the supplier immediately. Record the discrepancy first, because the act of asking sometimes produces a corrected document and the original state then becomes hard to reconstruct.
Photograph the label as received, with the lot number and strength legible. Keep the certificate as supplied, unaltered. Note the date, who received the shipment, and the condition of the package. Receiving and inspecting a peptide shipment covers the ten-minute protocol this fits into, and lot traceability and recordkeeping covers the file the record belongs in.
Quarantine the vial. Not because a mismatch means the material is bad, but because material of uncertain identity should not enter work while its identity is uncertain, and separating it takes seconds at this point and is impossible later.
Triage by which field disagrees
| Field that disagrees | Usual cause | Severity |
|---|---|---|
| Supplier address or logo | Template or rebranding change | Clerical |
| Date format or issue date | Regional formatting | Clerical |
| Product name spelling or synonym | Catalogue name against systematic name | Low — confirm the sequence |
| Strength or fill | Transcription, or the wrong label applied | Serious |
| Lot number | Wrong certificate sent, or wrong vial packed | Serious |
| Compound identity | Wrong product entirely | Stop |
How serious each kind of mismatch is
The top three rows resolve with a corrected document and no change to the material. The bottom three do not, and the distinction between them matters: a strength mismatch may be a label error on correct material, a lot mismatch may be a paperwork error on correct material, but in both cases you cannot tell which from the outside, and that is the whole problem.
The name mismatch that is not an error
The most frequent apparent discrepancy is a name. A label carrying a catalogue designation and a certificate carrying a systematic name, or a development code, are describing the same molecule in two vocabularies.
The resolution is always the sequence. A certificate that states the sequence settles the question regardless of what either document calls the compound; one that gives only a name has not. Reading peptide nomenclature covers how sequences, fragments and modifications are written, which is the vocabulary needed to confirm two names describe one molecule.
Where a compound family has several members differing by length, a name mismatch is more serious, because the names differ by a number that is easy to transpose. Confirming the residue count against the stated sequence is the check.
Lot number mismatches
A lot number is the link between a vial and everything known about it. When the number on the vial does not appear on the certificate, the certificate describes different material, and nothing in it can be relied on for the vial in front of you.
Two scenarios produce this. The supplier sent the wrong certificate, in which case the correct one exists and arrives on request. Or the wrong vial was packed, in which case the material is not what was ordered and the certificate is irrelevant. These look identical from the receiving bench.
The distinguishing question is whether the supplier can produce a certificate matching the lot on the vial. If they can, it was a paperwork error. If they cannot, the vial is unidentified material and should be returned rather than used. How to verify a certificate of analysis covers confirming the document directly with the issuing laboratory, which is worth doing when a lot number has already been in question.
The category that should stop work
A compound identity mismatch — the label naming one molecule and the certificate another, where the two are not synonyms — is not a clerical problem. It means either the wrong product was shipped or the documentation system that connects products to certificates is not reliable.
Either conclusion affects more than the vial in hand. If the supplier's packing or documentation can produce this error once, other shipments from the same source warrant checking, including ones already accepted. Counterfeit and mislabelled research material covers what else to look at when identity is in doubt.
The correct action is to stop using material from that supplier until the cause is explained, not merely to replace the vial. A replacement resolves the instance; an explanation resolves the risk.
How to raise it
A useful message states facts and asks one question. The order reference, the lot number as printed on the vial, the lot number as printed on the certificate, the field that disagrees, and a request for either a corrected document or a replacement. Photographs attached.
What makes this work is specificity. 'The paperwork does not match' invites a general reply; 'the vial is marked lot X and the certificate is for lot Y, please send the certificate for lot X or advise' invites a specific one. It also creates a record of exactly what was asked and when.
Keep the original documents after a correction arrives. A corrected certificate replaces the original for use, but the original is part of the history of that lot in your records, and a pattern of corrections across several orders is itself a finding. The supplier audit checklist covers where that pattern belongs in an assessment.
The mismatch that is in your own records
Not every discrepancy originates with the supplier. A surprising share are transcription errors made at receiving — a lot number typed with a transposed digit, a strength recorded from the order rather than from the vial.
The symptom is identical: records and documents disagree. The difference is that this version is discovered later, usually when someone tries to reconcile a piece of work against a certificate and finds no matching lot. By then the vial may be finished and the packaging gone.
Two habits prevent most of it. Record from the vial rather than from the order confirmation, because the vial is the object the work will use. And have a second person check the lot number on any entry that will be cited in work, which costs seconds and catches transpositions reliably.
Lot traceability and recordkeeping covers the record itself; this is about getting the first keystroke right, which is where the error rate actually lives.
Who decides, and how quickly
A discrepancy found at receiving sits with whoever opened the box, and that person frequently cannot decide whether work may proceed. Naming the decision in advance is what stops a quarantined vial becoming a vial that quietly enters use because nobody said otherwise.
Two things make this work in practice. A standing rule that quarantine is the default for any mismatch, so the receiving step needs no judgement — judgement comes later, from whoever is authorised to release it. And a named person who makes that call, so the question has somewhere to go rather than circulating.
Writing an SOP for peptide receipt and storage covers putting that in writing, and chain of custody inside a laboratory covers the record of who held what and when, which is the other half of the answer when a query arrives months later.
Preventing the common cases
Most clerical mismatches are caught at receiving rather than prevented, and the receiving check is therefore where the effort belongs. Confirming lot number, compound and strength against the certificate before a vial goes into storage takes under a minute and catches almost everything.
The habit that makes it reliable is checking before the packaging is discarded, because the packaging frequently carries the only external record linking the shipment to the order. Labeling and identification covers keeping a vial traceable once it has left its box.