Chain of Custody and Sample Traceability

Establish the sample's starting point

Begin with the source material, the sample identifier and the collection event. An identifier written on a submission form becomes useful when a record connects it to the material from which the sample was taken. Lot numbers and traceability explains the separate role of the container's lot reference.

As a documentation example, FDA's ICH Q7 guidance connects laboratory samples with material or source, batch or other code, sampling date and relevant receipt details. [A6] Q7 concerns pharmaceutical ingredients; its record structure is not evidence of Knockout Labs compliance or proof that these records have been supplied.

For a lot review, distinguish “sample submitted as lot DEMO-L1” from “sampling record connects this sample to lot DEMO-L1”. The first reports a label or declaration. The second requires a supporting record. Neither phrase, by itself, establishes that the sample represents every container in the lot.

Follow transfers and changes of identifier

EPA's sample-management procedure treats custody as both control of the sample and a documented history of possession. It records collection information and transfers through to laboratory receipt. [A5] This is an environmental field procedure, used here as a documentation example rather than a rule for research-peptide suppliers.

The following is a suggested reading checklist. It is not a validated sampling or transport procedure.

An accession number is the laboratory's reference for a received sample. It need not be identical to the supplier's lot number. Different identifiers can be legitimate when their relationship is documented; copying one number into every field would not improve the evidence.

Work through a fictional missing handover

All identifiers, times and events in this example are invented. The times share one stated time zone, UTC.

A precise review note would say: “The supplied records connect DEMO-R9 to DEMO-S7 and lot DEMO-L1, but custody between dispatch and laboratory receipt is not fully documented.” It would not say that substitution occurred. Missing documentation and evidence of substitution are different findings.

Ask whether an existing carrier, transfer or receipt record resolves the interval. Do not invent a handover signature, rewrite the original entry or assume that a later report authenticates every earlier event. Matching a certificate to a batch and container covers the separate document-matching exercise.

Custody does not establish representativeness

A complete history for one sample shows what happened to that sample. It does not explain whether the collection plan adequately represented a bulk lot, several containers or a changing material. That requires the sampling rationale and relevant procedure.

Similarly, a recorded storage interval is not proof that the material stayed within appropriate conditions. Where conditions matter, request the applicable instruction and available condition or deviation record. Do not infer a universal temperature, transport duration or retention period from this guide.

A retained sample is material kept for possible later examination. Ask which sample or lot it came from, how it is identified and what handling history is recorded. Retention does not automatically make an old sample equivalent to the material originally tested, and this page does not confirm a Knockout Labs retention arrangement.

Ask for the missing connection

A focused request names the two records you cannot connect: “Please clarify how laboratory sample DEMO-204 relates to the submitted sample and source lot, and whether any receipt exception was recorded.” Replace the fictional references with the exact identifiers in your own documents.

The sourcing and release overview provides context for supplier documentation. Batch release, quarantine and rejection covers the material's decision status, which a custody record alone cannot establish. Return to the quality-documentation hub for the broader evidence routes.