Preparing for an ISO/IEC 17025 or NATA assessment often leads labs to search for a checklist as something to confirm everything is “covered” before the assessor arrives.

Checklists can be useful. But on their own, they can also be misleading.

In Part 3 of this series, we looked at how to prepare for an ISO 17025 assessment in a structured and practical way.

This article builds on that foundation by outlining what assessors are actually looking for, and how to think about a checklist in a way that reflects real assessment expectations.

Download a practical ISO 17025 audit checklist (PDF)

What an ISO 17025 Audit Checklist Should Really Do

A checklist should not be a list of clauses to tick off. It’s too easy to tick something off without really checking.

It should help you confirm that your laboratory can demonstrate:

• Competence — staff, methods, and decisions are technically sound
• Control — processes are consistent and understood
• Traceability — results can be followed from request to report
• Responsiveness — issues are identified and managed effectively

If a checklist does not test these, it is unlikely to reflect how an assessment will be conducted.

The ISO 17025 Audit Checklist

The sections below reflect how assessors typically move through a laboratory, not the order of the standard.

1. Contract Review and Request Handling

Can your laboratory demonstrate that work is clearly defined before it begins?

Check:

• Requests are reviewed before acceptance
• Methods are appropriate and agreed
• Any deviations are authorised
• Customer requirements are understood

What assessors look for:
Clear decision-making at the start of the process, not assumptions.

2. Methods and Technical Validity

Are your methods fit for purpose and correctly applied?

Check:

• Methods are current and controlled
• Validation or verification is appropriate
• Staff understand the limitations of methods
• Any modifications are justified

What assessors look for:
Confidence that results are technically valid, not just that they are documented.

3. Equipment and Calibration

Is equipment suitable and under control?

Check:

• Equipment is calibrated and traceable to the relevant standards
• Maintenance is performed and recorded
• Equipment status is clearly identified
• Out-of-tolerance situations are managed

What assessors look for:
Evidence that the equipment supports reliable results at all times.

4. Measurement Uncertainty (Where Applicable)

Can your laboratory justify the uncertainty associated with results?

Check:

• Uncertainty is determined where required (Are your measurements quantitative, semi-quantitative, or qualitative?)
• The approach is appropriate to the method
• Staff understand how it is applied
• Results are reported correctly

What assessors look for:
Practical understanding and application with current information, not theoretical documentation.

5. Sampling (If Applicable)

Is sampling controlled and representative?

Check:

• Sampling plans are defined
• Staff are trained and competent
• Environmental or situational factors are considered
• Records are complete

What assessors look for:
Confidence that samples represent what they are supposed to.

6. Handling of Test and Calibration Items

Is sample integrity maintained?

Check:

• Samples are uniquely identified
• Storage conditions are controlled
• Chain of custody is clear
• Deviations are recorded

What assessors look for:
Traceability and protection of samples from receipt to disposal.

7. Quality Control and Monitoring

Is the laboratory actively checking the validity of results?

Check:

• QC activities are defined and performed
• Results are reviewed and acted upon
• Trends are monitored
• Failures trigger appropriate action

What assessors look for:
Ongoing confidence in results, not retrospective checking.

8. Staff Competence

Are staff demonstrably competent for their roles?

Check:

• Training and competency are defined
• Authorisations are current
• Competence is periodically reviewed through ongoing demonstration of competence in the performance of activities
• Staff understand their responsibilities

What assessors look for:
Confidence at the bench level, not just records.

9. Reporting of Results

Are reports clear, accurate, and complete?

Check:

• Reports include all required information in ISO/IEC 17025 and the method
• Results are traceable to work performed
• Uncertainty is reported where required
• Authorisation is controlled

What assessors look for:
Reports that can be relied on by the customer.

10. Nonconformances and Corrective Action

Are issues properly identified and addressed?

Check:

• Nonconformances are recorded
• Root causes are considered
• Corrective actions are implemented
• Effectiveness is reviewed

What assessors look for:
Systems that learn — not systems that close issues quickly.

11. Internal Audits

Are internal audits meaningful?

Check:

• Audits cover all relevant areas
• Findings are realistic
• Actions are followed up
• Audits reflect actual practice

What assessors look for:
Internal audits that genuinely test the system.

12. Management Review

Is the system being actively managed?

Check:

• Inputs, as required in the Standard, are complete and relevant
• Outputs lead to action
• Decisions are documented
• Improvement is evident

What assessors look for:
Engaged leadership, not a procedural exercise.

Common Mistakes When Using Checklists

Many labs rely heavily on checklists but still encounter issues during assessments.

Common problems include:

• Treating the checklist as a compliance exercise
• Focusing on documents rather than evidence
• Overlooking how processes connect
• Not testing how the system works in practice

Remember: A checklist is a tool, not a substitute for understanding your system.

How to Use This Checklist Effectively

To get real value from a checklist:

• Walk through a real job, not just documents
• Ask “can we show this?” rather than “do we have this?”
• Involve staff who perform the work
• Focus on clarity and consistency

This approach aligns far more closely with how assessments are conducted.

What Comes Next

A checklist helps confirm readiness, but preparation also depends on how labs engage during the assessment itself.

If you haven’t already, it’s worth understanding how to approach assessors and the assessment process constructively.

Our recent article on Working With NATA Assessors: What Laboratories Should Know gives you all the answers!

FAQs

What is an ISO 17025 audit checklist?
An ISO 17025 audit checklist is a tool used to assess whether a laboratory meets the requirements of the standard and can demonstrate competence, control, and valid results.

How do you prepare for an ISO 17025 audit?
Preparation involves reviewing technical processes, ensuring records are complete, confirming staff competence, and testing how the system operates in practice.

What do ISO 17025 assessors look for?
Assessors look for evidence of valid results, controlled processes, competent staff, and effective management of risks and nonconformances.

If your lab would benefit from a structured, practical review before an upcoming assessment, MAS Management Systems can assist with preparation in a way that reflects how assessments actually operate. Get in touch at info@masmanagementsystems.com.au, or call Maree on 0411 540 709.

Remember, you don’t have to do this alone!

Catch up on our Accreditation Readiness series:

Part 1: ISO/IEC 17025 Accreditation: What Laboratories Actually Need to Know

Part 2: Working With NATA Assessors: What Laboratories Should Know

Part 3: How to Prepare for an ISO 17025 Assessment (Without the Panic)