What you'll learn
- Apply ALCOA+ to a record
- Name the nine ALCOA+ principles and what each one asks
- Explain how audit trails and unique logins protect electronic records
Apply the ALCOA+ principles to judge whether a lab record is trustworthy, and fix one that is not.
Why it matters
Every decision a lab supports (a patient's diagnosis, the release of a vaccine batch, a published discovery) is only as good as the records behind it. Regulators found that many serious problems were not bad science but bad records: missing data, backdated entries, results re-run until they passed. Data integrityData being complete, consistent and accurate throughout their life. means data are complete, consistent and accurate throughout their life. The ALCOA+ principles are the shared checklist regulated labs use, and they are good practice in any lab.
ALCOA
The original five, popularised at the US FDA:
- AttributableThe ALCOA principle that you can tell who recorded the data, who did the work, and when.: you can tell who recorded the data and who did the work, and when. Initials or signatures on paper; unique user logins (never shared passwords) on instruments and software.
- Legible: readable and permanent for as long as the record must be kept. Ink, not pencil; no erasing; electronic files in formats that can still be opened.
- ContemporaneousThe ALCOA principle that data are recorded at the time the work is done, not later from memory.: recorded at the time the work was done, not later from memory or scrap paper.
- Original: the first record (or a verified "true copy"). The printout from the balance, the raw instrument file, the notebook entry. Transcribed numbers are not the original.
- Accurate: correct, with no errors or editing that is not documented. Changes are recorded with who, when and why, leaving the original visible.
The "+"
Later guidance added four more:
- Complete: all data, including repeats, failed runs and re-tests, are kept. Nothing is deleted or left out.
- Consistent: entries follow the expected sequence, with dates and times in order and the same units and formats.
- Enduring: records last for the required retention period (bound notebooks, backed-up systems).
- Available: records can be found and read when needed, for review, audit or inspection.
Some organisations use ALCOA++, adding traceability, but the core idea is the same.
Electronic records
Most lab data now live in instruments, LIMS and electronic notebooks. In the US, FDA rules on electronic records and signatures (21 CFR Part 11) apply to many regulated systems. Integrity features include unique logins, audit trailsSystem logs that record every create, change and delete of electronic data with who, when and why. that log every create, change and delete with who, when and why, and controlled backups. A common inspection finding is a shared "lab" login, which makes every result non-attributable.
A worked example: audit a record
Here is a QC record for a pH check of a buffer:
Buffer lot B-0912 pH spec 7.30-7.50
Result: 7.41 Checked by: Lab Date: (blank)
Note on sticky note attached: "1st reading 7.62 - recalibrated, re-ran"Check it against ALCOA+:
| Principle | Problem |
|---|---|
| Attributable | "Lab" is not a person. Who measured it? |
| Contemporaneous / Consistent | No date or time, so you cannot place it in sequence. |
| Original | The first reading lives on a loose sticky note, not in the record. |
| Complete | The out-of-spec reading (7.62) is not part of the official record. |
| Accurate | Was the meter calibrated before the first reading? No record. |
A compliant version:
2026-10-23 09:12 Buffer lot B-0912, spec pH 7.30-7.50.
pH meter #2, calibration check 09:05 with pH 7.00/10.00 buffers: FAILED slope.
Recalibrated 09:08 (pass, slope 98.7%). Reading 1 (before recal) 7.62 - invalid,
meter failed calibration check; deviation DEV-0331 opened.
Reading 2 09:12: 7.41 (PASS) -- A. Patel (AP)
Reviewed 2026-10-23 11:30 -- R. Gomez (RG)Every value is kept, every action is attributable and dated, and the reason the first reading was invalid is documented and linked to a deviation. In a GMP lab, simply re-testing until a result passes ("testing into complianceRe-testing until a result passes without investigating the failure, a serious GMP violation.") without an investigation is a serious violation.
Common mistakes
- Shared logins or signing for someone else.
- Writing on scrap paper and copying later.
- Deleting or not recording failed runs.
- Backdating an entry to "fill a gap". Late entries must be marked as late, with the actual date written.
- Unreviewed changes to electronic data with the audit trail turned off.
Quick recap
- ALCOA: Attributable, Legible, Contemporaneous, Original, Accurate.
- Plus: Complete, Consistent, Enduring, Available.
- Keep every result, including failures; document every change with who, when and why.
- Electronic systems need unique logins and audit trails (21 CFR Part 11 in many US regulated labs).
- FDA guidance on data integrity is at fda.gov; read the current version there. Checked on 2026-10-23.
Key terms (5)
- Data integrity
- Data being complete, consistent and accurate throughout their life.
- Attributable
- The ALCOA principle that you can tell who recorded the data, who did the work, and when.
- Contemporaneous
- The ALCOA principle that data are recorded at the time the work is done, not later from memory.
- audit trails
- System logs that record every create, change and delete of electronic data with who, when and why.
- testing into compliance
- Re-testing until a result passes without investigating the failure, a serious GMP violation.