Laboratory Sample Traceability

Sample traceability is the ability to reconstruct the history of a material: where it came from, what was done to it, and under what conditions it was kept at each stage. Traceability is maintained through a combination of labelling and documentation, and it links a physical sample to its written record in a way that can be followed at any later point. The overview below is educational and describes general good practice; it does not constitute a protocol for any specific use of a material.

In research, traceability matters because results should be reproducible. If a material cannot be linked back to its specification and storage history, it is difficult to assess whether an experiment was conducted with material in the expected condition, or to replicate the work in the future with confidence.

Traceability can be thought of as a chain of identity extending from the source of a material through every step of its time in the laboratory. The chain begins when a material is received and its identity is recorded at the point of receipt. It continues through storage, noting where and under what conditions the material is kept. It extends through any handling or use, and it concludes when the material is exhausted, transferred, or disposed of. A gap in any link of this chain creates a period in the material’s history that cannot be accounted for.

Maintaining a continuous chain does not require complex systems. The basic requirements are that the material is labelled clearly at all times, that its location and condition are recorded whenever they change, and that the records are kept where they can be found alongside the material they describe.

What a label must carry

A label identifies a sample unambiguously. At minimum it typically carries the material name or identifier, the batch or lot number, and any relevant dates such as date of receipt or, if reconstituted, the date of preparation. Where multiple vials of the same material are in use, the label distinguishes them from one another and connects each to its own record.

Durability and legibility

A label is only effective if it remains readable throughout the sample’s time in the laboratory. Labels on vials stored at low temperatures must adhere reliably in cold environments, and ink must remain legible. A label that detaches or becomes illegible breaks the identity link between the physical sample and its records, which is a traceability failure regardless of how complete the written records are.

A laboratory record is the written complement to the label. Where the label carries identity and batch information, the record carries the history: when the material was received, where it was stored, when it was handled, and who was responsible at each stage. The connection between the label and the record is typically the batch identifier or a unique sample reference that appears on both. As long as that connection is maintained, the sample and its history can be read together.

For general guidance on what to record and how to keep records usable over time, see Laboratory Documentation Best Practices and Laboratory Record Keeping Best Practices. For how batch identifiers work and what they carry, see Research Material Batch Identification.

A gap in traceability is a period in a sample’s history that is not accounted for in its records. Gaps can arise from missing labels, incomplete records, or failures to note transfers and changes in condition. Even a single gap makes it impossible to guarantee the continuous identity of a sample from source to use. In research where reproducibility is the goal, this matters because results can only be attributed to a specific, well-characterised material if that material’s history is known.

Maintaining traceability is therefore not a bureaucratic exercise but a practical requirement for research integrity. For the related concept of chain of custody, which addresses the formal transfer of materials between individuals or locations, see Chain of Custody in Research Environments. Our general approach to material identification is described on the Quality page.