Audit Trail Review: step-by-step operational method
Introduction
Audit Trail Review requires method, expertise and a solid understanding of GxP systems.
This guide provides a structured workflow for reviewing audit trails from HPLC/GC, LIMS, MES, SCADA and batch systems, turning the process into an efficient, audit-ready routine.
🔧 Step-by-step guide
1. Identify the relevant audit trails
Classify the system’s audit trails into:
- critical data
- non-critical data
- configuration / user management
According to the guide, this classification must already be defined during URS and system validation.
2. Filter the critical events to be reviewed
For QC (HPLC/GC):
- chromatogram reprocessing
- manual integrations
- data exclusions
- modifications to methods or sequences
For LIMS:
- changes to results
- status changes (review, approval)
- deleted tests
For Manufacturing:
- changes to CPP parameters
- alarms and operator responses
- steps repeated or cancelled
- manual overrides in SCADA/PLC
3. Analyse anomalies
Assess whether the event is:
- covered by procedure
- justified and documented
- consistent with timestamps, roles and electronic signature
- requiring deviation, OOS, investigation or change control
4. Document the review
- electronic comments (e.g. “Audit Trail Reviewed”)
- electronic signature on the dataset
- summary report filtered on relevant events
⚠️ Watch out for…
- inconsistent timestamps → possible system clock manipulation
- “Admin” user modifying data → critical violation of Attributable
- repeated reprocessing → potential attempt to force results
- missing signatures → failure to follow process steps
❌ Common mistakes and operational solutions
Mistake: printing thousands of unfiltered log lines
Solution: filter only “significant changes”, as recommended in CDS guidance.
Mistake: considering ATR an IT activity
Solution: QC and Manufacturing must perform the review; QA validates and oversees.
Mistake: missing justification for changes
Solution: make the “Reason for Change” field mandatory.
📦 Short checklist
- critical audit trails identified
- filters applied for significant events
- reprocessing / changes / deletions verified
- consistency of roles and electronic signatures checked
- alarms and operator actions correctly assessed
- review properly recorded
Realistic scenario
During an HPLC analysis, the audit trail shows five consecutive reprocessings of the same chromatogram.
The review checks:
- missing justifications
- minimal differences between versions
- no deviation opened
→ The review identifies a potential attempt to alter the results. QA opens an investigation.
Conclusion
An effective Audit Trail Review requires method, smart filtering and critical interpretation. Explore the full guide on GuideGxP.com.
