A restock is a supply event, not a fresh analytical dossier. In UK laboratories, the arrival of a familiar catalogue item can create a comfortable assumption: the compound has been ordered before, the vial looks the same, the Internal Test Reference (ITR) matches an earlier delivery, so the evidence must carry over. That assumption is too loose for an in-vitro assay booking. An ITR can be a useful documentation pointer, but it is not a substitute for checking the batch-specific Certificate of Analysis (CoA), the label reference and the handling conditions that apply to the material in front of you. What an Internal Test Reference Captures After a Restock In…