Lot traceability in practice

Traceability fails quietly. It fails at the moment a container is decanted into an unlabelled tube, or when a batch is reordered and the new material is added to a shelf position that still carries the old label. Neither event produces an error at the time; both make it impossible to reconstruct, later, which material produced which result.

Capture at receipt, not at use

The single highest-value habit is recording the lot number at the point of receipt, in the same system that will later hold the experimental record. By the time material is being used, the container may already be a secondary one.

• Catalog number and lot number, transcribed from the container rather than from the packing note.
• Date of receipt and the condition on arrival, including whether cold-chain packaging was still cold.
• Where the certificate for that lot is stored, or the identifier that retrieves it.
• The storage location the material was placed into.

Secondary containers inherit the lot, or they inherit nothing

Any container that material is transferred into needs the lot number on it. A label carrying only the compound name is a label that will be ambiguous the first time a second lot enters the laboratory. Where container size makes a full label impractical, an internal identifier that resolves to the lot is adequate — the requirement is that the chain can be walked backwards, not that every label is complete on its own.

Retention outlives the material

Certificates should be retained for as long as any result derived from that material might be examined, which is usually considerably longer than the material itself lasts. Retention periods are set by the institution's records policy, by the funder, or by the regulatory framework the work sits under, and are typically measured in years after publication or submission rather than after consumption of the vial.