COA lot number does not match the vial: what to do before using or rejecting the lot

Why a mismatch matters

A certificate of analysis describes one lot. If the number on the certificate is not the number on the vial, the certificate tells you nothing verifiable about what is in your hands. Supplier lookup tools are built on that link: Evolve asks you to enter the batch number from your label to retrieve its certificate, Bachem asks for the product number and the lot number printed on the label or invoice, and Cayman's product page asks for batch numbers to download or request available product inserts and QC documents. [1] [2] [3]

Pharmaceutical good manufacturing practice makes the same point formally. US rules for drug manufacturers require each lot of a component to be identified with a distinctive code and its status recorded as quarantined, approved or rejected, require receipt checks of labelling, and hold components in quarantine until examined and released. [7] [8] Those rules do not apply to research-chemical suppliers or most research labs; we cite them only as a well-tested model of lot traceability.

Step 1: photograph and transcribe before anything else

Capture the evidence while the packaging is intact, because suppliers set short claim windows. Peptides EU asks for contact within 48 hours of delivery with the order reference and photos when a batch does not match its COA, and OMNI says claims after 48 hours of confirmed delivery cannot be reviewed. OMNI's list of valid claims covers damaged, wrong, compromised or missing items and does not mention certificate mismatches, so raise a mismatch within that window anyway. [5] [6]

• Photograph each vial label in focus, with the lot or batch number legible.
• Photograph or save the certificate exactly as received (paper insert, PDF or lookup page).
• Photograph the outer packaging and any packing slip that carries a lot number.
• Transcribe both numbers into your receiving log character by character.
• Note the delivery date and time from the carrier's tracking.

Step 2: rule out a formatting difference

Some mismatches are not different lots. Check whether one document adds a prefix, a suffix, a date stamp or leading zeros, or whether one shows a batch number and the other an internal order or report number. Evolve's lookup refers only to a batch number, and Bachem distinguishes the product number (entered without suffix) from the lot number. [1] [2] If the core sequence of characters is identical, ask the supplier to confirm in writing that both refer to the same lot rather than deciding yourself.

Check also whether the certificate came from the supplier or from a third-party laboratory. Peptides EU says it publishes selected independent certificates from Janoshik Analytical, and Evolve says its reports are issued by independent labs; a third-party report may carry the lab's own sample number as well as the supplier's batch number. [4] [1]

Step 3: quarantine and request the right certificate

Label the vials as on hold, store them at the label's stated condition, and record the status in your inventory. The GMP model above holds components in quarantine until they are examined and released. [8]

Then write to the supplier. Peptides EU asks customers to include the order reference and batch number so it can help quickly. [4] Evolve provides a certificate lookup by batch number, and Cayman's product page lets you download or request available documents by batch number, so try the label number there first. [1] [3] Bachem's analytical data sheet lookup needs the product and lot number. [2] Our guide to requesting a COA has a template email.

Decision table: what the answer means

Use the supplier's written reply to classify the problem, then record the decision.

Step 4: log the outcome and decide

Write down what was found, who confirmed it, and the decision: released, rejected or replaced. The GMP model records each lot's status as quarantined, approved or rejected; a simple research log can use the same three words. [7] If you rely on a supplier certificate at all, the same rules show how cautious manufacturers are: they accept a supplier's report of analysis only with at least one specific identity test of their own and after establishing the reliability of the supplier's analyses. [9] For important work, consider an independent identity test on the lot before release.

If the outcome is a replacement, the new vials will carry a new lot and need the same check.