Validation or verification?
ISO/IEC 17025 requires either verification (clause 7.2.1.5) or validation (clause 7.2.2) for every method a laboratory uses. Getting this decision right avoids unnecessary work as well as assessment findings.
| Situation | Required study |
|---|---|
| Standard method used within its scope, unmodified | Verification |
| Laboratory-developed method | Validation |
| Non-standard method | Validation |
| Standard method used outside its scope (e.g. another matrix) or modified | Validation |
Performance characteristics we evaluate
Selectivity
Showing that other components in the matrix do not bias the result.
Working range and linearity
Suitability of the calibration model and the range in which results are reliable.
LOD and LOQ
For environmental testing, the limit of quantification must sit comfortably below the legal limit value.
Trueness
Bias from certified reference materials, recovery studies or proficiency testing results.
Precision
Repeatability and within-laboratory reproducibility (intermediate precision).
Robustness
Sensitivity of the method to small changes in temperature, time or reagent lot.
Validation data are also the main input to measurement uncertainty estimation, so planning both together saves time.
Our validation approach
- Intended use and acceptance criteria, agreed in writing before any experiments.
- Experimental design: replicates, concentration levels, matrices and reference materials.
- Data collection with your team and traceable raw data.
- Statistical evaluation: outlier tests, regression, F- and t-tests as appropriate.
- Report and approval against the pre-defined criteria.
- Ongoing monitoring with control charts and proficiency testing.
What is method verification?
Verification demonstrates that you achieve the published performance of a standard method in your own laboratory. Typically trueness, precision and the limit of quantification are compared with the criteria in the method standard or legislation. Even though it is narrower than validation, verification still needs a plan and a report.
Deliverables
- Validation/verification plan with acceptance criteria
- Calculation templates and statistical evaluation files
- Validation and verification reports ready for approval
- Quality control plan for routine performance monitoring