A result is only as trustworthy as the trail behind it. If a lab cannot say which vial a sample came from, when it was opened and who handled it, even a careful measurement becomes hard to interpret or repeat. For peptides, which are often bought in small lots, split into aliquots and stored for months, that trail breaks easily.
This guide covers the practical side of record-keeping for research peptide samples: receipt logs, labels, sample tracking and the data-integrity ideas regulators summarise as ALCOA+. Those principles come from guidance written for regulated pharmaceutical work (GxP). A research lab does not have to be regulated to benefit from them. They are a good description of what makes any record reliable.
ALCOA+ in Plain Terms
The World Health Organization's guideline on data integrity (WHO Technical Report Series 1033, Annex 4, 2021) says data and records should be attributable, legible, contemporaneous, original and accurate, and also complete, consistent, enduring and available. That combined list is commonly called ALCOA+.
The UK Medicines and Healthcare products Regulatory Agency (MHRA) GxP data integrity guidance (2018) explains that ALCOA was the original set of data-quality attributes and that the "+" was added later to emphasise the extra requirements. MHRA states there is no difference in expectations whichever acronym is used.
Here is what each letter means for an ordinary lab notebook or sample log.
| Attribute | What it means | Example in a peptide lab |
|---|---|---|
| Attributable | You can tell who did it and when | Initials and date on every entry |
| Legible | It can be read and understood, permanently | No pencil, no unexplained abbreviations |
| Contemporaneous | Recorded at the time the work was done | Balance reading written down immediately |
| Original | The first record, or a verified true copy | The balance printout, not a retyped value |
| Accurate | Correct and free from errors | Units and lot numbers checked |
| Complete | Nothing missing, including repeats and failures | A rejected weighing is noted, not erased |
| Consistent | Entries follow a logical sequence | Dates and times run in order |
| Enduring | Lasts for the retention period | Bound notebook or backed-up system |
| Available | Can be retrieved when needed | Indexed so a lot can be traced quickly |
WHO also defines a true copy as a copy verified, by a dated signature or a validated process, to contain the same information as the original, including the context that describes it. That matters if you scan paper records or export data from an instrument.
Logging a Sample at Receipt
The receipt entry is the start of the trail. A useful receipt log records:
- Date received and who received it.
- Product name exactly as labelled, including any salt form or modification shown on the label.
- Supplier and lot or batch number from the label.
- Stated quantity per container and the number of containers.
- Condition on arrival: seal intact, packaging dry, any temperature indicator.
- Where it was stored and at what temperature.
- Documents received with the shipment, if any, and where they are filed.
If the label says one thing and a document says another, write down both and resolve it before use. Our guide The Label Is Not the Test explains why the label alone does not establish identity or purity.
Assigning an Internal Sample ID
Supplier lot numbers are not always unique inside your lab. Two suppliers can use similar formats, and one lot may be split into many containers. Many labs assign their own internal ID at receipt, for example a year, a running number and a container suffix (2026-014-A, 2026-014-B).
The internal ID links:
- the supplier's lot number,
- the receipt log entry,
- every aliquot or solution made from that container, and
- every experiment that used it.
Labelling Containers and Aliquots
A container label should let someone who has never seen it before work out what it is without opening a notebook. At a minimum:
- Internal ID
- Compound name (no private shorthand)
- Lot number
- Date received or prepared
- Storage condition
- Initials of the person who prepared it
For a solution made in the lab, also include the solvent and the concentration with units and, where relevant, the parent container ID. Use labels and ink that survive the storage conditions. Ordinary paper labels can peel or smear in freezers and in condensation. Cryo-rated labels or printed labels are more durable. This supports the "enduring" and "legible" parts of ALCOA+.
Aliquoting a stock into single-use portions is common because it limits repeated warming and opening of the main container. Each aliquot needs its own label that traces back to the parent. See Storing Lyophilized Peptides for the storage side of this.
Tracking Use: The Sample History
Each time material is taken from a container, record:
- Date, time and initials
- Amount removed (with the weighing record, if weighed)
- What it was used for (experiment or notebook page reference)
- Container state afterwards (for example, returned to −20 °C)
A simple usage log makes it possible to answer questions that come up later. Which experiments used lot X? How many times was this vial opened? Was it out of the freezer when the power failed? Our guide on Weighing Peptide Powders lists what to capture for each weighing.
Corrections, Repeats and Failed Runs
Two habits make a big difference.
Correct without erasing. On paper, draw a single line through the error so it stays readable, write the correction next to it, and add initials, date and a short reason. Do not use correction fluid or overwrite. In electronic systems, the equivalent is an audit trail. MHRA describes an audit trail as a secure record of creation, additions, deletions or changes to information that does not obscure or overwrite the original, so the "who, what, when and why" of each change can be reconstructed.
Keep the failures. A weighing that was discarded, a run that failed system suitability, a sample that looked wrong: all of these belong in the record. Recording only the runs that worked is exactly what the "complete" part of ALCOA+ is meant to prevent.
Metadata: The Context That Makes Data Usable
WHO defines metadata as data that provide the context needed to understand other data. For a peptide experiment, metadata include the instrument and method version used, the units, the sample ID, the analyst and the date. A chromatogram file without its sample ID and method is hard to interpret. Store metadata with the result, not in someone's memory.
Paper, Electronic and Hybrid Records
Many labs run a mix: a paper notebook, instrument software and spreadsheets. MHRA recognises such hybrid systems, where paper and electronic records together form the original record. The risk is that links between them break. Practical safeguards:
- Write the electronic file name or run ID into the paper notebook.
- Write the internal sample ID into the instrument's sample field.
- Back up electronic data on a schedule, and test that backups can be restored.
- Keep spreadsheets that do calculations under version control, so a changed formula is visible.
Retention and Retrieval
Decide in advance how long records will be kept and where. WHO describes archiving as long-term storage and protection of records so they remain available and unchanged. For a research lab, this usually means:
- Bound or numbered notebooks stored securely when full.
- Electronic data on managed storage, not a personal laptop.
- An index by internal ID and lot number, so one sample's whole history can be found in minutes.
What a Supplier Record Can and Cannot Tell You
Your lab's records cover what happens after a container arrives. Supplier documents describe the material before it arrives. Keep them filed against the same internal ID, but regard them as one input, not as proof of what is in a specific container. If identity or purity matters for your work, the most direct evidence is testing done or commissioned by your own lab. See How to Read a Peptide Analytical Report for what such a report should contain.
A Short Checklist
- Receipt log with date, lot, condition and storage location
- Internal ID assigned and written on every container
- Durable labels with name, lot, date, storage and initials
- Usage log for every withdrawal
- Corrections that leave the original readable, with reason
- Failed and repeated runs recorded
- Electronic files linked to sample IDs and backed up
- Records indexed so any lot can be traced end to end
FAQ
Is ALCOA+ a legal requirement for a research lab? The WHO and MHRA documents are written for regulated GxP work. Outside that setting they are not binding, but they are widely used as a description of good record practice.
Do I need an electronic lab notebook? No. Paper records can meet every ALCOA+ attribute if they are bound, written in permanent ink, dated, signed and stored properly. Electronic systems help with search and audit trails, but only if they are configured and backed up.
What is the single most useful habit? Writing the internal sample ID everywhere: on the container, in the notebook and in the instrument file. It links everything else.
Sources
- World Health Organization. Guideline on data integrity. WHO Technical Report Series No. 1033, Annex 4, 2021: https://cdn.who.int/media/docs/default-source/medicines/norms-and-standards/guidelines/inspections/trs1033-annex4-guideline-on-data-integrity.pdf
- UK Medicines and Healthcare products Regulatory Agency. 'GXP' Data Integrity Guidance and Definitions, Revision 1, March 2018: https://assets.publishing.service.gov.uk/media/5aa2b9ede5274a3e391e37f3/MHRA_GxP_data_integrity_guide_March_edited_Final.pdf
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