Posted on 18 Dec,2025

Common Mistakes Labs Make During Accreditation Assessments

Accreditation assessments—whether for ISO/IEC 17025, ISO 15189, ISO/IEC 17020, or any other standard—are meant to evaluate a laboratory’s technical competence and quality management system.
However, many laboratories unintentionally make avoidable mistakes that lead to nonconformities, delays, or even suspension of accreditation.

Understanding these common mistakes helps labs prepare better and ensures smoother, faster, and more successful assessments.

1. Incomplete or Outdated Documentation

Many labs falter because their documents are:

·         Not aligned with the latest standard requirements

·         Not approved or controlled

·         Not updated after changes in processes

·         Different from what is actually practiced

Tip: Documentation must reflect the actual practices inside the laboratory—not just what looks good on paper.

2. Poor Understanding of the Accreditation Standard

Some labs implement a QMS without fully understanding the clauses of ISO/IEC 17025 or ISO 15189.
This leads to:

·         Misinterpretation of requirements

·         Missing key procedures

·         Inconsistent implementation

Tip: Train personnel on the intent of the standard, not just the wording.

3. Inadequate Method Validation or Verification

This is a very common technical nonconformity. Labs often:

·         Use methods without validation

·         Skip verification for standard methods

·         Fail to calculate measurement uncertainty correctly

·         Do not document the validation process

Tip: Every method must be validated/verified with proper records before use.

4. Poor Measurement Uncertainty (MU) Estimation

Labs Often:

·         Have improper understanding of MU principles itself, due to lack of training

·         Do not calculate MU at all

·         Use copied formulas without relevance

·         Cannot explain the MU model during assessment

Tip: MU must be practical, test-specific, and understood by technical staff.

5. Lack of Traceability in Calibration

Labs sometimes use equipment calibrated by non-accredited providers or without traceability to national/international standards.

Tip: Ensure all calibrations are done by laboratories accredited by an, ILAC/APAC MRA, Accreditation Body.

6. Gap Between Procedure and Practice

Many labs show well-written SOPs, but during witnessing, the assessor finds:

·         Technicians follow a different practice

·         Steps are skipped

·         Safety or quality controls are ignored

Tip: Staff must follow procedures consistently and be trained regularly.

7. Ineffective Internal Audits

Internal audits are often:

·         Done as a formality

·         Conducted by untrained auditors

·         Too general (not process-based)

·         Missing technical evaluation

·         Not followed by corrective actions

Tip: Internal audits must be as rigorous as external assessments.

8. Poor Handling of Nonconformities

Common gaps include:

·         Not identifying nonconformities in time

·         Superficial root cause analysis

·         Weak corrective actions

·         Not performing effectiveness checks

Tip: Use a structured RCA method (5 Why, Fishbone, etc.) and validate effectiveness.

9. Lack of Training and Competency Records

Labs often struggle to show:

·         Defined competency criteria

·         Skill assessments

·         Training records

·         Authorization for testing/reporting

Tip: Competency should be proven with records + practical evaluation, not only training certificates.

10. Equipment Issues

Frequent equipment-related mistakes:

·         Missing calibration stickers

·         Expired calibrations

·         Broken or poorly maintained instruments

·         No maintenance logs

·         Instruments used beyond allowable ranges

Tip: Maintain a complete equipment lifecycle record.

11. Incomplete Quality Control (QC) Practices

Some labs perform QC but:

·         Do not record results properly

·         Do not analyze trends

·         Do not take action on out-of-control results

Tip: Implement regular QC with trend analysis and documented actions.

12. Weak Data Integrity and Record Keeping

Labs may store data in:

·         Unsynchronized files

·         Handwritten, unclear logs

·         Systems without security or backups

Tip: Ensure data is traceable, secure, and tamper-proof.

13. Poor Communication with Assessors

Labs sometimes:

·         Hide issues instead of discussing them

·         Provide incomplete information

·         Do not understand assessor queries

·         Fail to follow up on corrective actions

Tip: Maintain open, transparent communication.
Assessment is not an audit to “catch mistakes”—it’s a process to improve competence.

Conclusion

Most accreditation challenges arise not because labs lack capability, but because they:

·         Do not fully understand the standard

·         Ignore critical details

·         Fail to maintain real-time documentation

·         Treat accreditation as a one-time activity instead of a continuous process

By avoiding these common mistakes and preparing well, laboratories can achieve accreditation smoothly and maintain consistent technical competence.