Sample provenance · O-025
Sample handling and chain of custody
A result describes the sample that reached the laboratory. Custody records connect that sample to an item, batch and collection event. Without them, the analytical result can be sound while the product claim remains unproven.
Sample handling and chain of custody document where a test sample came from, who possessed it, how it was sealed, stored and transferred, and whether its condition changed before analysis. An unbroken record strengthens the link between the result and the sampled vial, but one vial still cannot establish the composition or uniformity of an entire batch without a justified sampling plan.
Provenance and representativeness are separate. Custody can show that the laboratory tested the submitted vial; a sampling plan is needed to explain what that vial can represent.
What should a custody record contain?
- AcquisitionWho selected and obtained the item, from where, on what date and under which order or sampling plan.
- IdentifiersProduct name, batch or lot, container description, photographs, unique sample code and seal number.
- TransfersEach handover, date, time, sender, recipient and reason for transfer.
- Storage and transportTemperature, light protection, packaging, delays and any excursions relevant to sample stability.
- Laboratory receiptCondition on arrival, seal integrity, mass or count received and any discrepancy.
- Sub-sampling and disposalWhich portion was tested, what remains, and how retained material was controlled.
How strong is the product link?
| State | Evidence present | Defensible conclusion |
|---|---|---|
| Documented and unbroken | Independent acquisition, unique seals, recorded transfers and laboratory receipt. | The result can be linked to the sampled item, subject to method limits |
| Partial | Some identifiers or transfers exist, but gaps remain. | The link is qualified; unresolved gaps should be named |
| Undocumented | Seller-supplied image or report with no acquisition and custody record. | The result cannot be attached confidently to the product held by the reader |
Why is one vial not a batch?
A batch can vary because of filling, mixing, packaging, degradation or substitution. Testing one unit can demonstrate what was found in that unit and can identify a serious failure. It cannot show the distribution of results across all units.
A batch-level conclusion needs a sampling objective, defined population, selection method, number of units and plan for handling variation. Seller selection can introduce bias because the supplier controls which unit reaches the laboratory.
Custody asks, “Was this the item tested?” Sampling asks, “What wider group can this item represent?”
Common breaks in the chain
- No unique sealThe submitted container cannot be distinguished from a replacement after purchase.
- Batch number recorded lateThe record may have been reconstructed after the result rather than captured at acquisition.
- Uncontrolled storageHeat, moisture or delay may change the sample before testing.
- Seller-selected sampleThe tested unit may not represent items supplied to customers.
- Certificate-only evidenceA document without acquisition records cannot show that its sample came from the vial under review.
Continue the evidence check
Set conditions for independent testing
Independence depends on who obtained and controlled the sample.
Match the document to the vial
Reconcile batch and certificate identifiers after provenance is recorded.
Questions readers ask
Does chain of custody prove the peptide is genuine?
No. It supports the link between the sampled item and the laboratory result. The analytical method must still establish the claimed identity, purity, quantity or other attribute, and clinical or regulatory claims remain outside the custody record.
Is a blind purchase always representative?
A blind purchase reduces seller control over sample selection, but one purchased vial still represents one unit. Batch-level conclusions need a justified sampling plan, and storage or transport after purchase must remain documented.
Can photographs replace a custody form?
Photographs can strengthen identification by recording packaging, labels, seals and condition. They do not record every transfer, storage condition or sub-sampling event, so they should support rather than replace a controlled custody record.
Why do storage conditions matter?
Peptides and related products can change with heat, moisture, light or time. If transport and storage are unknown, a result may describe degradation after acquisition rather than the condition of the item when supplied.
Primary sources and update triggers
- GOV.UK: Sample records and chain of custody: a UK regulatory example of sampling plans, custody records, storage and reporting traceability
- UKAS: Laboratory accreditation and ISO/IEC 17025: competence, impartiality and consistent operation within a defined testing scope
- Eurachem: The Fitness for Purpose of Analytical Methods: method validation, detection capability, precision and fitness for purpose
Editorial experience
From our work: how we checked this page
For topical-map item O-025, Sample handling and chain of custody was checked as a distinct editorial task, not treated as a generic peptide page. We reviewed 3 unique external sources and 6 internal destinations in the page, then checked that the opening answer, headings, source descriptions and linked next steps stayed within the same claim boundary. The count records links in the published page and is not a claim that every source carries equal evidential weight.
Eleni Kiromitis checked the laboratory and scientific wording, drawing on direct experience commissioning laboratory tests and reviewing certificates of analysis and chromatograms. She checked whether each method was matched to the attribute it can measure, whether sample and batch limits remained visible, and whether the conclusion stopped where the analytical record stopped. Yianni Kiromitis retained responsibility for source verification, editorial decisions and correction management.
We did not use patient experience, a personal treatment outcome, seller testimony or an assumed product identity to support this page. The publication did not independently test a vial for this review. Where a page refers to a laboratory result, that result applies only to the named sample, method and attribute. We kept uncertainty beside the conclusion, recorded which source supports each material claim, and checked that the visible review date matches the publication record. A new controlled study, regulator update, corrected source, analytical report or credible safety signal can trigger reassessment through the public correction route.