Labeling and Chain of Custody in the Laboratory

Accurate documentation and traceability are the foundation of reproducible, defensible research. Whether you are working with peptides in a cell biology lab, running preclinical studies, or preparing samples for analysis, maintaining a clear chain of custody and proper labeling practices is essential. This article outlines best practices for documentation and tracking in the research laboratory.

What is chain of custody?

Chain of custody is a complete record of the handling, possession, and location of a sample or reagent from the moment it enters the laboratory until it is used, archived, or disposed of. It serves several critical purposes:

• Reproducibility. Later researchers (or auditors) can trace exactly how and when a sample was handled, prepared, and analyzed.
• Integrity. A documented chain ensures that no unauthorized modification, substitution, or contamination occurred.
• Compliance. Many regulatory frameworks—including GLP (Good Laboratory Practice), ISO 17025, and FDA 21 CFR Part 11—explicitly require chain-of-custody documentation.
• Audit trail. In the event of a discrepancy or dispute, a clear record shows who had access to a sample and when.

Best practices for sample labeling

Clear, consistent labeling prevents mix-ups and enables rapid identification in the lab. Key principles:

• Use a standardized format. Include: (1) sample ID or project code, (2) compound name and lot number, (3) date of receipt or preparation, (4) initials of the person who prepared or received the sample, (5) any relevant hazard or storage requirement. Example: "BPC-157 Lot 2026-07-15 / P001 / 08.10.26 / AMS / Freeze-dried, Store –20°C".
• Legible labels. Handwritten labels can fade or become illegible. Use waterproof, permanently affixed labels (barcode labels are best) or indelible marker on tubesif using a labeling system.
• Label the container, not just the cap. Caps can get swapped or replaced. The primary container and the associated tube (if in a rack) should both be labeled.
• Redundancy for critical samples. For samples used in published research or regulatory submissions, use both a printed barcode label and a handwritten backup identifier.

Documentation in the laboratory notebook

Every interaction with a sample must be recorded in a laboratory notebook (paper or electronic). The entry should capture:

• Date and time of the action (day and time are both important for some protocols).
• Sample identification (lot number, ID, or barcode).
• Action taken (received from supplier, weighed, reconstituted, aliquoted, analyzed, etc.).
• Conditions (temperature, solvent, duration, equipment used).
• Results or observations (color, clarity, absorbance reading, yield, etc.).
• Personnel (full name or initials, plus date signed).

If using a paper notebook, write in permanent ink, avoid cross-outs (use a single line through errors and initial/date), and never tear out pages. If using an electronic lab notebook (ELN), ensure it is validated, provides timestamping, prevents retroactive edits without audit trails, and enforces role-based access control.

Tracking transfers and storage transitions

Every time a sample changes location or handler, document it:

• Who transferred it (name/initials).
• When (date and time).
• From where (previous location: refrigerator, freezer, shelf, lab bench).
• To where (new location).
• Condition on transfer (appearance, any changes).

A transfer log or a Laboratory Information Management System (LIMS) can automate this: when a sample is scanned into storage or checked out by an analyst, the system automatically logs the event with a timestamp.

Digital systems and automation

Larger labs often adopt electronic tools to maintain chain of custody:

• Electronic Lab Notebooks (ELNs) like Benchling, LabArchives, or Conquer provide timestamped entry, prevent unauthorized editing, and generate audit trails for regulatory compliance.
• LIMS (Laboratory Information Management Systems) track samples from receipt through analysis, generating automatic events and preventing manual data-entry errors.
• Barcode scanning integrates with LIMS to log every movement of a sample in real time.

Even paper-based labs benefit from a master sample inventory spreadsheet updated whenever a vial is used or archived, reducing reliance on memory.

Disposal and archival

Document the end-of-life for samples as carefully as you document arrival:

• Archive retention. If the research may be published or audited, retain a representative sample and document the storage location for the retention period (often 3–5 years or longer for FDA-regulated work).
• Disposal. Record the date, method, and personnel responsible for disposal (chemical waste, biohazard, or standard trash). Some peptides, especially in large quantities, may require special handling.

Why it matters for your research

Whether you are working on a university project, a company-sponsored study, or exploratory research, a robust chain of custody protects your work. When you publish or present, reviewers and readers want to know that every data point is traceable to its source. A clear, documented chain of custody is that proof.

Research peptides with documented purity

Every vial of research peptide we supply includes a Certificate of Analysis (COA) that documents identity and purity. This becomes part of your chain of custody from day one, establishing the quality baseline for your experiments:

View research peptides

Sources & further reading

• Sapio Sciences — Initiating a Chain of Custody Program in the Laboratory
• LabKey — What Is Chain of Custody In The Lab?
• Lab Manager — Evidence Chain of Custody Best Practices for Labs
• U.S. FDA — 21 CFR Part 11 — Electronic Records; Electronic Signatures

Universe Peptide publishes research-focused education for the scientific community. Products are for laboratory research only. See more in our News & research updates.