Understanding Internal Audits for NABL Accreditation

Internal audits are one of the most critical — and most misunderstood — requirements of NABL accreditation. Done correctly, internal audits are your most powerful tool for finding and fixing quality problems before NABL assessors do.

ISO 15189:2022 requires a formal internal audit programme that covers all activities within the laboratory’s scope of accreditation at least once per audit cycle. Here’s everything you need to know.

What Must Be Audited?

Your internal audit programme must cover all ISO 15189:2022 clauses and all aspects of laboratory operations, including:

• Management system requirements (QMS, risk management, document control)
• Technical requirements (personnel, equipment, calibration)
• Pre-analytical processes (sample collection, receipt, storage)
• Analytical processes (testing, QC, calibration)
• Post-analytical processes (result review, reporting, critical values)

Who Can Conduct Internal Audits?

Internal auditors must be trained (minimum 16-hour internal auditor training course) and must be independent of the area being audited. In small labs, this can be challenging — consider cross-department auditing or engaging an external auditor for certain sections.

The Internal Audit Process

1. Annual audit plan: Document which areas will be audited, by whom, and when.
2. Audit checklist: Develop checklists for each area based on ISO 15189:2022 requirements.
3. Conduct the audit: Interview staff, observe processes, review records, and compare against SOPs.
4. Report: Document findings, including conformances, observations, and non-conformances.
5. CAPA: Raise corrective actions for all non-conformances. Track to closure.
6. Management review input: Internal audit results must be presented at the management review.

Common Internal Audit Non-Conformances

• Internal auditors auditing their own area
• Audit findings not linked to formal CAPA
• Incomplete audit records
• Certain clauses never audited
• Corrective actions not verified for effectiveness