The plate reader returns a flat signal where the positive control should have produced a clear response. On the bench sits the vial the run was built around — sourced from a UK supplier, part-used — and behind it an unopened second vial from the same delivery. The temptation is to tidy up: strike the material from the worksheet, or move it quietly to the shelf reserved for stock that “works”. Neither response survives scrutiny in a laboratory that takes COSHH seriously. A failed in-vitro control run is an event to be recorded, and the vial attached to it is an inventory item whose status, history and documentation must stay intact while the failure is investigated.
Separate the assay failure from the material question
A control failure is an experimental observation, not a verdict on the vial. The useful discipline is to triage causes in a fixed order: cell line and passage number, media and serum lot, diluent and reconstitution arithmetic, plate layout and edge effects, instrument calibration and operator technique — and only then the material’s own history. Jumping straight to “the peptide is bad” is as unsound as ignoring the vial altogether, and it produces inventory records that later mislead.
The material history is precisely what a COSHH-aware inventory exists to hold. Before any status change, assemble the reconstitution date, the diluent lot, the number of freeze–thaw cycles the vial has already been through, storage temperature records and the time the container spent out of the freezer during plate set-up. A vial thawed four times and left at ambient temperature through a long working session is a different proposition from one opened once, sampled and returned to −20°C within minutes. That distinction belongs in the record, not in someone’s memory of the afternoon.
Interim status should be quarantine — investigation, neither approved nor rejected. Both of those are decisions; quarantine is a holding position that keeps the material visible, prevents it being drawn into a second run by a colleague who sees a familiar label, and preserves the option to release it once the cause is understood. Write the reason in the status field itself, with the initials of the person who applied it and the month and year of the change.
While the vial is held, check the documentation against the specific batch rather than against marketing copy. The supplier states that a certificate of analysis accompanies each product, covering HPLC purity and identity, and the homepage lists “CoAs Janoshik Analytical Reports”; open the actual document that came with the batch and confirm it matches the label reference before drawing conclusions. Be aware that restocked products may carry the same Internal Test Reference as earlier stock — an ITR links to associated sample testing reports, but it does not confirm that separate deliveries came from the same production lot or were separately independently tested. Vial cap colours and other packaging may vary between deliveries, and cap colour is not an indicator of identity, analytical quality or manufacturing origin. Purity headlines on a website can change, so treat published figures as current at the time of reading and reconfirm them on the live page and on the batch CoA.
One further point belongs in the investigation note rather than the status field: the supplier’s FAQs state that its peptides contain trace amounts of mannitol as an excipient. If the assay in question is sensitive to sugar alcohols or to osmolarity effects in the well, that observation is worth recording as a possible confounder.
What the inventory entry must capture once a run has failed
The entry should be built around a minimum field set: material name and SKU; the label reference, which the supplier formats as SKU plus expiry (for example BPC10-03/27); supplier and purchase reference; the CoA file location and any internal test reference shown; the COSHH assessment identifier and its review date; the version of the safety data sheet held; storage condition and location code; quantity and unit; arrival date and condition on arrival; and current status. Where a run has failed, the line should also carry the deviation identifier, the run and sample identifiers, the operator, the reconstitution date, the diluent and volume used to prepare the working concentration for the in-vitro assay, and the cycle count to date. None of this is bureaucracy for its own sake — every one of those fields is a question someone will ask three weeks later.
Storage conditions should be recorded exactly as they are applied: lyophilised material at −20°C or below, sealed with desiccant, protected from moisture, heat and light, with repeated freeze–thaw cycles avoided. Once reconstituted, the vial is less stable and should be held at 2–8°C for short-term laboratory use only, with a disposal-by entry added at the point of preparation. Quarantined material should sit in a physically separate location, clearly labelled as under investigation and not for release, so that nothing is drawn into another experiment by convenience. Where the vial originates from a UK supplier such as Peptide uk, file the batch CoA against the inventory line itself rather than in a personal folder, so the documentation travels with the status history.
Every record must also state plainly that the material is for research use only and not for human or veterinary use. That line is not decorative: it prevents an entry from being read later as a clinical or veterinary stock item and anchors the vial to controlled laboratory and analytical work.
Deciding the outcome and keeping the audit trail honest
When the investigation closes, there are four defensible outcomes: release as originally recorded; release with a restriction, such as use only in non-quantitative work; continued hold pending supplier correspondence; or rejection and disposal by the waste route named in the COSHH assessment. Each requires a named approver and a written rationale. Rejection without evidence is as poor a record as release without review, and silent removal of a vial from the inventory is the worst outcome of all, because it removes the data that would show a pattern.
If a supplier query is warranted, preserve the evidence first: the vial, the packaging, the arrival condition notes, temperature records and the CoA file. The shop’s published terms state that no returns are accepted once goods are dispatched, with refunds limited to damage, incorrect supply or quality issues as set out in its Refunds & Returns Policy, so photographic and documentary evidence carries the weight in any correspondence. Quote the label reference — the SKU and expiry combination — when raising the query, because that is what links the vial to its batch documentation.
Finally, review the pattern. A single failed control run in an otherwise steady workflow points towards laboratory variables; repeated failures across operators on the same SKU deserve a batch-level conversation, a re-read of the CoA and ITR, and a formal supplier contact. Reconcile the physical shelf against the inventory after every deviation, confirm that quarantine items have not migrated, and make sure the failed run remains attached to the vial’s record as part of its history rather than being erased from it. The materials involved remain research-use-only items, not for human or veterinary use, and every handling decision should keep them inside that boundary.
