ISO 13485 internal audit methodology for medical device quality management systems.
Plan risk-based internal audit program:
| Risk Level | Frequency | Criteria |
|---|---|---|
| High | Quarterly | Design control, CAPA, production validation |
| Medium | Semi-annual | Purchasing, training, document control |
| Low | Annual | Infrastructure, management review (if stable) |
| Clause | Process | Focus Areas |
|---|---|---|
| 4.2 | Document Control | Document approval, distribution, obsolete control |
| 5.6 | Management Review | Inputs complete, decisions documented, actions tracked |
| 6.2 | Training | Competency defined, records complete, effectiveness verified |
| 7.3 | Design Control | Inputs, reviews, V&V, transfer, changes |
| 7.4 | Purchasing | Supplier evaluation, incoming inspection |
| 7.5 | Production | Work instructions, process validation, DHR |
| 7.6 | Calibration | Equipment list, calibration status, out-of-tolerance |
| 8.2.2 | Internal Audit | Schedule compliance, auditor independence |
| 8.3 | NC Product | Identification, segregation, disposition |
| 8.5 | CAPA | Root cause, implementation, effectiveness |
Verify auditor independence before assignment:
Conduct systematic internal audit:
| Method | Use For | Documentation |
|---|---|---|
| Document review | Procedures, records | Document number, version, date |
| Interview | Process understanding | Interviewee name, role, summary |
| Observation | Actual practice | What, where, when observed |
| Record trace | Process flow | Record IDs, dates, linkage |
Document Control (4.2):
Design Control (7.3):
CAPA (8.5):
See references/iso13485-audit-guide.md for complete question sets.
Document each finding with:
Requirement: [Specific ISO 13485 clause or procedure]
Evidence: [What was observed, reviewed, or heard]
Gap: [How evidence fails to meet requirement]
Example:
Requirement: ISO 13485:2016 Clause 7.6 requires calibration
at specified intervals.
Evidence: Calibration records for pH meter (EQ-042) show
last calibration 2024-01-15. Calibration interval is
12 months. Today is 2025-03-20.
Gap: Equipment is 2 months overdue for calibration,
representing a gap in calibration program execution.
Classify and manage audit findings:
| Category | Definition | CAPA Required | Timeline |
|---|---|---|---|
| Major | Systematic failure or absence of element | Yes | 30 days |
| Minor | Isolated lapse or partial implementation | Recommended | 60 days |
| Observation | Improvement opportunity | Optional | As appropriate |
Is required element absent or failed?
├── Yes → Systematic (multiple instances)? → MAJOR
│ └── No → Could affect product safety? → MAJOR
│ └── No → MINOR
└── No → Deviation from procedure?
├── Yes → Recurring? → MAJOR
│ └── No → MINOR
└── No → Improvement opportunity? → OBSERVATION
| Finding Severity | CAPA Depth | Verification |
|---|---|---|
| Major | Full root cause analysis (5-Why, Fishbone) | Next audit or within 6 months |
| Minor | Immediate cause identification | Next scheduled audit |
| Observation | Not required | Noted at next audit |
See references/nonconformity-classification.md for detailed guidance.
Prepare for certification body or regulatory audit:
Documentation:
Personnel:
Facility:
references/iso13485-audit-guide.md contains:
references/nonconformity-classification.md contains:
# Generate optimized audit schedule
python scripts/audit_schedule_optimizer.py --processes processes.json
# Interactive mode
python scripts/audit_schedule_optimizer.py --interactive
# JSON output for integration
python scripts/audit_schedule_optimizer.py --processes processes.json --output json
Generates risk-based audit schedule considering:
Output includes:
{
"processes": [
{
"name": "Design Control",
"iso_clause": "7.3",
"risk_level": "HIGH",
"last_audit_date": "2024-06-15",
"previous_findings": 2
},
{
"name": "Document Control",
"iso_clause": "4.2",
"risk_level": "MEDIUM",
"last_audit_date": "2024-09-01",
"previous_findings": 0
}
]
}
Track audit program effectiveness:
| Metric | Target | Measurement |
|---|---|---|
| Schedule compliance | >90% | Audits completed on time |
| Finding closure rate | >95% | Findings closed by due date |
| Repeat findings | <10% | Same finding in consecutive audits |
| CAPA effectiveness | >90% | Verified effective at follow-up |
| Auditor utilization | 4 days/month | Audit days per qualified auditor |