Common ISO/IEC 17025 Audit Nonconformities and How to Avoid Them

 

Testing and calibration laboratories play a critical role in industries such as pharmaceuticals, automotive, aerospace, power and food safety. For these organizations, NABL accreditation is more than a certificate it demonstrates technical competence, impartiality and reliability of test and calibration results.

Many laboratories face ISO 17025 audit non-conformities during assessments. These often include incomplete documentation, outdated calibration records, insufficient evidence of staff competence or weak ISO 17025 internal audits. In some cases, laboratories treat this certification as a paperwork requirement rather than a living management system, resulting in recurring compliance issues and failed outcomes.

Every non-conformity has consequences. It can undermine credibility, weaken customer trust and even jeopardize contracts with regulators, certification bodies or global clients. By understanding the common non-conformities in ISO 17025 and adopting corrective measures, laboratories can reduce risks, improve audit readiness and achieve accreditation with greater confidence.

This blog highlights frequent ISO/IEC 17025 compliance issues, explains why such audit findings occur and shares practical strategies to overcome these audit challenges.

WHAT IS ISO/IEC 17025?

ISO/IEC 17025 is the internationally recognized standard for testing and calibration laboratories. It specifies the general requirements for competence, impartiality and consistent operations, ensuring that laboratory results are valid, traceable and globally accepted.

Unlike ISO 9001, which focuses on quality management at an organizational level, ISO/IEC 17025 goes deeper into the technical requirements that directly influence laboratory outcomes. These include method validation, equipment calibration, staff competency, risk management and data integrity all of which are evaluated during ISO 17025 audits.

For organizations, achieving ISO/IEC 17025 accreditation brings several advantages:

• Recognition of technical competence by regulators, accreditation bodies and customers worldwide.
• Greater reliability of test and calibration results, minimizing disputes, re-testing and costly compliance failures.
• Support for regulatory compliance across critical industries such as pharma, food, environment and manufacturing.
• Enhanced customer confidence and market competitiveness both domestically and internationally.

ISO/IEC 17025 framework provides a structured compliance framework that helps laboratories reduce ISO 17025 audit non-conformities and operate with transparency, accuracy and credibility. This is why ISO/IEC 17025 compliance issues are taken so seriously they directly reflect whether a lab is audit-ready and able to meet global expectations.

Key Reasons to Implement ISO/IEC 17025

Organizations Implement ISO/IEC 17025 not only for recognition but also in response to increasing industry pressures, regulatory requirements and client expectations. The key drivers for implementation include:

• Integration with Global Supply Chains: As supply chains become increasingly international, only results from accredited laboratories are widely accepted. Implementation of ISO/IEC 17025 ensures laboratory outputs are recognized across border enabling global market participation.
• Commitment to Impartiality and Integrity: Beyond technical competence, laboratories must demonstrate impartiality and transparency. ISO/IEC 17025 introduces safeguards to prevent conflicts of interest and reinforce trust in laboratory practices.
• Customer and Stakeholder Demands: Global clients, regulators and certification bodies increasingly expect laboratories to operate in line with ISO/IEC 17025 standards. Accreditation often becomes a mandatory requirement for contracts, approvals and long-term partnerships.
• Consistency Across Operations: In the absence of a standardized framework, laboratories often struggle with variations in methods, record-keeping and reporting. This certification introduces a unified system that ensures results remain consistent, regardless of personnel changes or equipment variations.
• Mitigation of Non-Compliance Risks: Unplanned equipment failures, inadequate staff training or poor documentation can disrupt laboratory operations and create compliance gaps. Implementing ISO 17025 establishes structured processes to minimize these risks before they result in major non-conformities.
• Competitive Advantage: In highly regulated industries such as pharmaceuticals, food and aerospace organizations prefer working with accredited laboratories. Without NABL ISO 17025 laboratories risk losing business opportunities to competitors that demonstrate stronger compliance and reliability.

By adopting ISO 17025 certification standards laboratories move beyond basic compliance to build a robust framework for quality assurance, risk management and sustainable market leadership.

COMMON NON-CONFORMITIES IN ISO/IEC 17025 AUDIT AND THEIR FINDINGS

Common Non-Conformities in ISO/IEC 17025 Audit and Their Findings

Under Personnel (Clause 6.2), a common non-conformity observed is that competence is not demonstrated. Technical staff are not adequately evaluated for competence, ISO/IEC 17025 training records are incomplete, and there is no evidence of periodic skill assessment or competency evaluation.

In Equipment (Clause 6.4), calibration and equipment gaps are frequently identified. Equipment is used without valid calibration certificates, traceability to national or international standards is not established, and preventive maintenance records are incomplete or missing.

For Purchasing and External Services (Clause 6.6), supplier and external provider weaknesses are commonly noted. There are no evaluation records for external calibration providers, and there is a lack of evidence demonstrating that subcontracted services comply with ISO/IEC 17025 requirements.

Within Sample Management (Clause 7.4), sample handling and traceability gaps are often found. Sample labelling is incomplete, chain-of-custody records are not maintained, storage practices are poor, and traceability from sample receipt through to reporting is not adequately demonstrated.

Regarding Records and Data (Clause 7.5 / Clause 7.11), improper handling of data and results is a recurring issue. Raw data is not properly archived, laboratories rely on uncontrolled spreadsheets, and data validation as well as access control measures are inadequate.

Under Methods (Clause 7.2) and Measurement Uncertainty (Clause 7.6), method validation and measurement uncertainty weaknesses are observed. Test methods are used without proper validation, uncertainty evaluations are missing or insufficiently documented, and justification for method selection is not recorded.

For Complaints and Corrective Actions (Clause 7.9 / Clause 8.7), poor complaint handling and CAPA implementation are common. Customer complaints are not formally recorded, corrective actions are delayed or ineffective, and repeat non-conformities are observed across successive audits.

In Document Control (Clause 8.3), incomplete or uncontrolled documentation is frequently identified. Quality manuals, SOPs, and test methods are not updated, document version control is absent, and uncontrolled copies of documents are in circulation.

Under Risk and Impartiality (Clause 8.5 / Clause 4.1), weak risk management and impartiality oversight are evident. No risk register is maintained, threats to impartiality such as conflicts of interest are not documented, and preventive actions are missing.

Finally, for Internal Audit (Clause 8.8) and Management Review (Clause 8.9), deficient internal audits and reviews are observed. Internal audits are not conducted as per the planned schedule, audit findings are not closed, and management reviews lack key inputs such as risk, impartiality considerations, and customer feedback.

STRATEGIES TO ADDRESS NON-CONFORMITIES IN ISO 17025 STANDARDS

• Competence Not Demonstrated: Auditors frequently raise NCs when staff training records are incomplete or when competence evaluations are missing. For instance, in a audit of a pharma laboratory technicians operating GC instruments could not provide evidence of method-specific training. The NC was closed only after the lab implemented a competence matrix, linked ISO 17025 training to each analytical method and documented periodic performance checks. This ensured auditors could trace skills directly to responsibilities.
• Calibration and Equipment Gaps: This common finding is of instruments without valid calibration. In one automotive calibration lab torque wrenches were in active use despite expired calibration certificates making all results for that period unreliable. The lab corrected the NC by introducing a master calibration calendar with automated alerts and by tagging equipment to prevent use when certificates lapse. This practice now ensures audit readiness at all times.
• Supplier and External Provider Weakness: Many labs outsource calibration or testing without verifying the supplier’s accreditation. In a food testing lab, a subcontracted microbiology test provider was found to be non-accredited leading to rejection of outsourced reports. By creating a supplier evaluation checklist (including NABL/ISO 17025 scope review) the lab established evidence-based approval of external providers preventing recurrence of this NC.
• Sample Handling & Traceability Gaps: One materials testing lab was cited for poor sample traceability when auditors found multiple samples stored without unique identifiers. This created uncertainty about which results belonged to which client. The corrective action involved implementing barcode labelling, logging samples into a chain-of-custody register and defining storage protocols. This system not only satisfied auditors but also reduced internal mix-ups.
• Improper Handling of Data and Results: Data integrity issues are a major NC. In an environmental testing lab, auditors flagged uncontrolled Excel files used for recording water quality parameters formulas could be edited without authorization. The lab addressed this by migrating to a validated Laboratory Information Management System (LIMS), locking historical records and introducing access controls. This not only resolved the NC but strengthened client trust in data reliability.
• Method Validation & MU Weakness: Auditors often find that methods are applied without documented validation. In one pathology lab, a new PCR test was introduced without validation or uncertainty estimation. The NC was closed after the lab developed a validation protocol aligned with ISO/IEC 17025, performed inter laboratory comparisons and prepared a documented uncertainty budget. This gave confidence in method reliability during surveillance audits.
• Poor Complaint Handling & CAPA: A calibration lab received multiple client complaints about delayed reports but had no formal complaint log. During audit this was flagged as a repeat NC. The lab established a complaint register, linked it to CAPA workflows and reviewed trends in management meetings. Within 6 months, complaint closure times improved, demonstrating continual improvement to auditors.
• Incomplete / Uncontrolled Documentation: Document control is one of the most common NCs. In a power sector testing lab, auditors discovered technicians using outdated SOPs that conflicted with the current Quality Manual. The NC was closed after the lab implemented electronic document control with restricted access, version tracking and quarterly document reviews. This gave auditors confidence that only approved documents were in use.
• Weak Risk Management & Impartiality Oversight: In a recent audit, a laboratory director was found to be both managing client relations and approving test results for the same client a clear impartiality risk. The NC was resolved by introducing impartiality declarations, maintaining a risk register and assigning result approvals to independent technical staff. This demonstrated transparent governance to auditors.
• Deficient ISO 17025 Internal Audits and Reviews: One food testing lab had skipped internal audits for two consecutive years, resulting in multiple hidden NCs being discovered during external assessment. Corrective action included preparing an annual audit calendar ISO 17025 internal auditors training and ensuring management reviews addressed risks, customer feedback and audit outcomes. Subsequent audits showed significantly fewer NCs

BENEFITS OF IMPLEMENTATION ISO/IEC 17025 CERTIFICATION

• Holistic Quality Culture: Implementing ISO/IEC 17025 goes beyond technical compliance; it fosters a culture where quality is everyone’s responsibility. Staff at all levels become aligned with principles of accuracy, impartiality and transparency. This shift ensures that good practices are consistently applied, not just during audits. Over time, laboratories build an environment where excellence is embedded in day-to-day operations.
• Transparent Decision-Making: Reliable decisions depend on validated data, documented competence and controlled processes all central to ISO/IEC 17025. With evidence-based insights, management can make confident choices about methods resources and investments. This transparency also provides clarity for regulators and clients reviewing the lab’s operations. The result is stronger governance backed by traceable, defensible records.
• Strengthened Global Credibility: Accreditation under ISO/IEC 17025 signals international recognition of competence. Test reports and calibration certificates gain acceptance across borders without the need for revalidation. This credibility facilitates easier entry into global supply chains and collaborations with multinational clients. It positions laboratories as trusted world-class service providers.
• Streamlined Collaboration: Implementation brings structure to how teams share data, manage samples and communicate findings. Standardized documentation and reporting reduce misunderstandings and delays in multi-disciplinary projects. External stakeholders such as suppliers or clients also benefit from this consistency. As a result, collaboration becomes smoother and more productive strengthening professional partnerships.
• Future-Ready Operations: ISO/IEC 17025 promotes continual improvement and adaptation to change. Laboratories are encouraged to adopt digital tools such as LIMS, align with evolving industry standards and anticipate regulatory shifts. This future oriented approach ensures the lab remains competitive and compliant in dynamic industries. Instead of reacting to changes the organization stays prepared for them.
• Talent Retention and Attraction: Professionals value working in structured environments where competence is recognized and career growth is supported. ISO/IEC 17025 provides clear role definitions, training pathways and performance evaluations. This clarity helps retain skilled staff while also attracting new talent seeking stability and growth opportunities. Over time, the lab benefits from a motivated and capable workforce.
• Reputation for Reliability: Consistent implementation of ISO/IEC 17025 builds a reputation that extends beyond certification. Clients, regulators and partners begin to associate the laboratory with reliability and technical excellence. This reputation becomes a powerful differentiator in competitive markets, where credibility often drives contract decisions. Long-term, it reinforces the lab’s position as a preferred and trusted partner.

ISO/IEC 17025 is not just about passing an audit; it is about building a laboratory culture rooted in accuracy, impartiality and continual improvement. While common non-conformities such as incomplete documentation, calibration gaps, weak internal audits or data integrity issues can delay accreditation, addressing them with structured strategies strengthens both compliance and credibility. By effectively implementing ISO/IEC 17025 laboratories can reduce risks, enhance customer trust and position themselves as reliable, globally recognized partners in highly regulated industries.

HOW 4C CONSULTING HELPS YOU IMPLEMENT ISO/IEC 17025 IN YOUR ORGANIZATION?

At 4C Consulting, we bring 20+ years of expertise in testing and calibration environments to simplify ISO/IEC 17025 implementation. 10,000+ training hours and 50+ workshops into a structured end-to-end approach covers gap assessments, documentation support, competence management, equipment calibration schedules, risk registers, training and internal audits all tailored to your laboratory’s needs. By identifying potential non-conformities early and integrating best practices into daily operations, we ensure your systems are audit-ready, reliable and aligned with global expectations. Partnering with 4C means smoother NABL accreditation stronger client trust and long-term operational excellence. Book your Free ISO/IEC 17025 Gap Assessment today.