Why Compendial Methods Require Verification — Not Validation — in ISO/IEC 17025 Laboratories
Understanding the difference between method verification and validation when implementing standardized analytical methods.
By Ashley Dennis • Laboratory Quality Systems Expert
Published March 2026
Category: Laboratory Accreditation | ISO/IEC 17025
Reading time: ~4 minutes
- Compendial methods are already validated during their development.
- ISO/IEC 17025 laboratories typically perform verification rather than full validation.
- Verification confirms the laboratory can successfully implement the method.
- Insufficient verification documentation is a common accreditation assessment finding.
Analytical laboratories operating under ISO/IEC 17025 frequently rely on standardized analytical procedures published in recognized compendia such as pharmacopeias, regulatory methods, or international standards.
However, laboratories sometimes misunderstand the expectations surrounding these methods during accreditation assessments. One of the most common questions assessors encounter is whether compendial methods must be fully validated by each laboratory.
Under ISO/IEC 17025, the answer is generally no. Instead, laboratories must demonstrate method verification.
What Are Compendial Methods?
Compendial methods are standardized analytical procedures published by authoritative organizations or regulatory bodies.
- Pharmacopeial methods (USP or EP)
- International standards organizations
- Regulatory agency methods
- Industry consensus standards
ISO/IEC 17025 Requirements for Method Implementation
ISO/IEC 17025 requires laboratories to ensure that analytical methods used for testing or calibration are suitable for their intended purpose.
What Is Method Verification?
Method verification demonstrates that a laboratory can successfully implement a standardized analytical method within its own environment.
- Accuracy
- Precision
- Detection capability
- Repeatability
When Full Validation May Be Required
- Applying the method to new matrices
- Modifying the analytical procedure
- Using different instrumentation
- Operating outside the method scope
Common Assessment Findings
- No documented verification studies
- Incomplete performance evaluation
- No acceptance criteria
- Missing records
Establishing an Effective Verification Process
- Review scope of the method
- Evaluate instrumentation
- Perform performance checks
- Document results
- Authorize method for use
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Frequently Asked Questions
Do compendial methods require validation?
Generally no. Verification is typically required instead.
What does method verification demonstrate?
It confirms the laboratory can properly perform the standardized method.
When is validation required?
Validation may be necessary when a method is modified or used outside its intended scope.
Related Resources
- 7 Common ISO/IEC 17025 Nonconformities Found During Assessments
- Proficiency Testing vs Internal Quality Control
- What Happens When a Laboratory Fails Proficiency Testing?
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