ALCOA+ Data Integrity: A Practical Guide for Labs

ALCOA+ data integrity is a set of principles describing what trustworthy laboratory records look like. The acronym originated in regulated pharmaceutical settings, but it is just as useful in a research lab, where an experiment is only as reliable as the record of how it was done. This article explains each principle with paper and electronic examples and ends with a practical checklist.

What ALCOA+ stands for

ALCOA was originally five attributes. The “+” adds four more that became common in regulatory guidance from bodies such as the MHRA, FDA and WHO. Some organizations add “Traceable” and call the set ALCOA++.

Principle	Meaning	Paper example	Electronic example
Attributable	Who did it, and when	Initials and date on each entry	Unique login; actions linked to the user in the audit trail
Legible	Readable and permanent	Permanent ink; no pencil or correction fluid	Human-readable reports; data not in proprietary formats no one can open
Contemporaneous	Recorded at the time of the activity	Weights written directly in the notebook, not on scrap paper	Balance output captured directly; synchronized system clocks
Original	The first capture, or a certified true copy	Original printout attached, not a transcription	Native instrument data files retained
Accurate	Correct, with changes documented	Single-line strike-through with reason, initials, date	Changes logged with old value, new value and reason
Complete	All data, including repeats and failures	No torn-out pages; failed runs recorded	All runs in a sequence retained, including aborted ones
Consistent	Chronological, with consistent formats	Sequential page numbers and dates	Time-stamped records in a logical sequence
Enduring	Lasts for the retention period	Bound notebook stored safely	Validated backups on durable media
Available	Retrievable for review when needed	Indexed archive	Searchable archive; tested restore procedure

ALCOA+ data integrity in paper lab notebooks

Paper records remain common for sample preparation, weighing and observations. Good documentation practice for a notebook typically includes:

• bound notebooks with pre-numbered pages, so pages cannot be removed unnoticed;
• entries in permanent ink, made at the time the work is done;
• a title, date and objective at the start of each experiment;
• material identification for every reagent, including lot number and, where relevant, the certificate of analysis consulted;
• corrections by a single line through the original entry so it stays readable, with the reason, initials and date;
• unused space struck through so nothing can be added later;
• printouts and labels attached permanently and signed across the edge;
• review and countersignature by a second person where your lab requires it.

Avoid “transcription on the side”: writing a weight on a glove or a sticky note and copying it later breaks the Original and Contemporaneous principles, even if the number is correct.

Electronic records and audit trails

Most analytical data now begins life in software: chromatography data systems, balance software, plate readers and electronic lab notebooks. The principles are the same, but the controls are technical.

Access and attribution

• One user, one account. Shared logins make records unattributable.
• Role-based permissions, so that analysts cannot delete data or change system settings that affect results.
• Automatic session lock when a workstation is left unattended.

Audit trails

An audit trail is a secure, computer-generated, time-stamped record of who created, modified or deleted data, and why. A useful audit trail cannot be switched off by the people whose work it records. It only adds value if someone reviews it: many labs review the audit trail of a chromatographic sequence before approving its results.

Raw data and metadata

For chromatography, the raw data is not just the final area-percent value. It includes the data file, the instrument method, the processing method, integration events and any reprocessing history. Manual integration should be justified and traceable. If the same chromatogram was integrated several ways, all versions should remain visible. Our article on HPLC purity testing explains why integration choices can change a purity result.

Regulated systems

In regulated environments in the United States, 21 CFR Part 11 sets requirements for electronic records and electronic signatures, including audit trails, system validation and signature controls. Research labs are often outside its scope, but its concepts are a sensible model for any electronic system that holds important data.

Common data integrity gaps in research labs

• Spreadsheets with editable formulas and no record of who changed what.
• Instrument PCs with a generic administrator login.
• “Test” or “trial” runs deleted before the reported sequence.
• Data stored only on a local instrument drive with no backup.
• System clocks that drift or can be changed by users, undermining time stamps.
• Results copied into reports without a link back to the source file.

None of these require bad intent to cause problems. They make it impossible to reconstruct what happened, which is the real test of data integrity.

A practical ALCOA+ checklist

1. Can every entry be traced to a named person and a date?
2. Was each value recorded directly, at the time, in the official record?
3. Are original data files retained, along with methods and processing parameters?
4. Are corrections visible, explained and attributed?
5. Are failed, repeated and aborted runs recorded, not just the passing result?
6. Are reagent and material lot numbers recorded and linked to their COAs?
7. Are electronic records backed up, and has a restore been tested?
8. Could someone else find and understand the record years from now?

Recording supplier lot numbers is the link between your data and the material you used. Our sibling article on lot traceability in research supply covers that connection, and the Veridryx Testing Library lets you retrieve the lot-level COA that belongs in the record.

Frequently asked questions

Does ALCOA+ apply to research labs that are not regulated?

There may be no regulatory requirement, but the principles describe what makes any record trustworthy and reproducible. Many institutions and funders expect equivalent practices.

Is it acceptable to correct an entry in a lab notebook?

Yes, provided the original remains readable, the correction is dated and initialed, and the reason is stated. Erasing, overwriting or using correction fluid is not acceptable practice.

What is a certified true copy?

It is a copy verified, by a documented process, to contain the same information as the original, including relevant metadata. It can then stand in for the original record.

How long should lab records be kept?

Retention periods are set by institutional policy, contracts, funders or applicable regulations. The Enduring and Available principles require that records remain readable for that whole period.

References

1. MHRA, “GXP” Data Integrity Guidance and Definitions (2018).
2. U.S. FDA, Data Integrity and Compliance With Drug CGMP: Questions and Answers, Guidance for Industry (2018).
3. WHO, Guideline on Data Integrity, WHO Technical Report Series No. 1033, Annex 4 (2021).
4. 21 CFR Part 11, Electronic Records; Electronic Signatures.