Control of Nonconforming Work – A Practical Laboratory Approach

June 22, 2026

Introduction

Control of nonconforming work is a key requirement of ISO/IEC 17025.

Nonconforming work occurs when:

  • Results are incorrect or questionable
  • Processes deviate from procedures
  • Equipment fails
  • Requirements are not met

The goal is not to eliminate all issues — that is unrealistic.

The goal is to ensure that issues are identified, controlled, and managed effectively.

What Control of Nonconforming Work Should Achieve

An effective process should:

  • Identify problems quickly
  • Prevent further impact
  • Evaluate affected work
  • Communicate appropriately
  • Initiate corrective action

Common Gaps Observed in Practice

1. Late Identification

Issues are discovered after results are reported.

2. No Immediate Containment

Problems are allowed to continue or spread.

3. Incomplete Impact Assessment

Affected samples or data are not fully evaluated.

4. Poor Documentation

Records are incomplete or unclear.

5. Weak Communication

Clients or stakeholders are not informed when necessary.

Why These Issues Occur

  • Lack of clear procedures
  • Pressure to maintain productivity
  • Fear of reporting errors
  • Insufficient training

What Effective Systems Look Like

Strong systems demonstrate:

  • Immediate identification and response
  • Clear containment actions
  • Thorough impact evaluation
  • Transparent communication
  • Strong linkage to corrective action

Practical, Step-by-Step Approach

Step 1: Identify the Issue

Encourage prompt reporting of any deviation.

Step 2: Stop and Contain

  • Stop affected work if necessary
  • Isolate impacted samples or data

Step 3: Evaluate Impact

Ask:

  • What results are affected?
  • Has data been reported?
  • Are clients impacted?

Step 4: Communicate

  • Inform internal stakeholders
  • Notify clients if required

Step 5: Document Clearly

Record:

  • What happened
  • When
  • Who identified it
  • Actions taken

Step 6: Initiate Corrective Action

Link to root cause analysis and improvement actions.

Additional Considerations

  • Promote a culture where reporting issues is encouraged
  • Use trends to identify recurring problems
  • Integrate with risk management and internal audits

Advanced Insight

In mature systems:

  • Issues are identified early
  • Trends are analyzed proactively
  • Nonconforming work drives system improvement
  • Transparency is part of organizational culture

Key Insight

The effectiveness of a laboratory is not measured by the absence of errors, but by how well errors are managed.

Conclusion

Control of nonconforming work is critical for maintaining data integrity, compliance, and client trust.

A structured and transparent approach ensures that issues are managed effectively and do not recur.