Laboratories that fail to find their own gaps before an assessor does tend to pay for it in delayed accreditation, repeated surveillance visits, and rework that could have been avoided. A well-run ISO/IEC 17025 internal audit is the most reliable way to surface those gaps early, while there is still time to correct them quietly.
This article outlines the nonconformities most often raised against testing and calibration laboratories, explains why they occur, and sets out practical corrective actions. It is written for quality managers and technical leads preparing for assessment or surveillance.
Why the ISO/IEC 17025 Internal Audit Matters for Accreditation
ISO 17025 is the international benchmark for laboratory competence, impartiality, and consistent operation. Under the ISO/IEC 17025:2017 revision, internal audits are a required part of the management system, not an optional exercise. The laboratory must plan them, define criteria and scope, report results to relevant management, and act on findings without undue delay.
A thorough internal audit also strengthens the laboratory accreditation process as a whole. Assessors generally look for evidence that the laboratory can detect its own problems. A lab that arrives with its findings already logged, investigated, and closed demonstrates a mature laboratory quality management system far more convincingly than one that claims to have none.
Planning an Audit of a Testing Laboratory
Effective programs to audit testing laboratories share a few traits. They are risk-based, they cover every clause of the iso 17025 standard over a defined cycle, and they use auditors who are independent of the work being examined.
Consider these planning points:
- Give higher audit frequency to areas with recent complaints, staff changes, new methods, or past findings.
- Audit both vertically (one sample traced from receipt to report) and horizontally (one requirement, such as traceability, checked across all methods).
- Keep auditors independent of the activity audited, which can mean using trained staff from another section or an external auditor in small laboratories.
A practical ISO 17025 audit checklist should be built from the clauses of the standard and tailored to the laboratory’s own procedures. Generic checklists tend to produce generic findings, so questions should reference actual methods, equipment, and records.
Common ISO/IEC 17025 Nonconformities and Corrective Actions
The following areas repeatedly generate ISO/IEC 17025 nonconformities. The examples are illustrative scenarios, not statistics.
1. Impartiality and Confidentiality Not Demonstrated
Many laboratories hold a policy statement but have never assessed impartiality risks. A typical finding: a lab tests products for a client that is also a significant funding source, with no documented risk review.
Corrective action: Maintain a risk register that identifies threats to impartiality, records the evaluation, and is reviewed periodically. Ensure confidentiality agreements cover staff, subcontractors, and external bodies.
2. Personnel Competence Records Incomplete
Auditors often find that authorizations exist, but evidence of competence does not. A technician may be performing a method with no recorded training, supervised practice, or competence assessment.
Corrective action: Define competence requirements per role and method, and keep records of training, observation, and authorization. Monitor ongoing competence through proficiency results and periodic re-evaluation.
3. Equipment Calibration and Metrological Traceability Gaps
This remains one of the most frequent areas of concern. Examples include overdue calibrations, certificates not reviewed against method requirements, and intermediate checks that were never defined.
Corrective action: Keep a controlled equipment register with calibration due dates and review every certificate for uncertainty, correction factors, and suitability. Define intermediate checks where the stability of equipment warrants them.
4. Method Validation and Verification Weaknesses
Laboratories sometimes use standard methods without verifying that they can achieve the stated performance. Others modify a method without revalidating it.
Corrective action: Document verification for every standard method before first use, and full validation for non-standard or modified methods. Records should show the acceptance criteria and the results against them.
5. Measurement Uncertainty Not Evaluated
Uncertainty estimates are sometimes missing, outdated, or copied from another laboratory’s work without justification. Reports may also omit uncertainty where it affects the validity of a decision.
Corrective action: Prepare uncertainty budgets specific to each method and review them when equipment, conditions, or procedures change. Establish clear rules for when uncertainty must appear in reports.
6. Weak Assurance of the Validity of Results
Some laboratories participate in proficiency testing but never analyze unsatisfactory results. Others have no documented plan for ongoing monitoring.
Corrective action: Create an annual monitoring plan that combines proficiency testing, interlaboratory comparisons, replicate testing, and control charts. Investigate every outlier through a recorded root cause analysis.
7. Ineffective Corrective Action and Risk-Based Thinking
Corrective actions are frequently closed after addressing only the symptom. A repeated finding at the next audit usually signals that the root cause was never identified.
Corrective action: Use a structured root cause method, define actions that remove the cause, and verify effectiveness after a set period. Link risks and opportunities to the management review.
8. Document and Record Control Lapses
Obsolete procedures remain at workstations, handwritten corrections are unsigned, or technical records cannot reproduce the original test conditions.
Corrective action: Control document versions, withdraw superseded copies, and ensure technical records contain enough detail to repeat the test.
Special Considerations: Medical Device Testing Lab Accreditation
Laboratories pursuing medical device testing lab accreditation face additional scrutiny because their results can affect patient safety and regulatory submissions. Sample identification, environmental control, traceable reference materials, and report accuracy deserve particular attention in the audit program. Laboratories should also confirm that their scope of accreditation matches the specific tests they offer to manufacturers.
Also read : ISO/IEC 17025: Requirements for Testing and Calibration Laboratories
Turning Findings into Audit Readiness
Findings alone do not improve a laboratory. The value lies in how they are handled afterward:
- Classify each finding by clause and severity.
- Assign an owner and a realistic deadline.
- Verify that the corrective action worked, not just that it was completed.
- Feed trends into management review so recurring themes receive resources.
For laboratories preparing for ISO 17025 certification (more precisely, accreditation to the standard by a recognized body), this cycle provides the evidence an assessor expects to see. Teams that want structured support with gap assessments, internal audit training, or documentation review can approach specialist consultants such as FDASindia.
Key Takeaway
An internal audit is only as useful as the honesty behind it. Laboratories that plan audits on risk, use a tailored checklist, and close findings through genuine root cause analysis enter the assessment with fewer surprises and a stronger case for competence. To begin, run one vertical audit on a recently issued report and see what the records reveal.
Contact FDAS India today to plan your accreditation journey with fewer surprises and a faster path to approval.
Call Us : +91 8448278215 / +91 8448278215
Email : fdasindia@hotmail.com
