LabQMHub Editorial Team · ISO 15189:2022 Quality Management Series
Before a laboratory ever reports a single patient result using a new test method, it must answer a foundational question: does this method actually perform the way it claims to, in this specific laboratory, with this specific equipment and these specific operators? Method verification and validation are how a laboratory answers that question with objective evidence rather than assumption.
ISO 15189:2022’s Clause 7.3 requires this evidence-gathering process for every examination method before clinical use, distinguishing between verifying an already-validated commercial method and validating a method that has not been independently established — a distinction with real practical and regulatory consequences.
Verification vs. Validation: A Critical Distinction
Verification applies to methods that are already validated by the manufacturer or another authoritative source — the laboratory’s job is to confirm the method performs as claimed under its own local conditions, typically a more limited study than full validation. Validation, by contrast, applies to laboratory-developed tests, modified commercial methods, or methods used outside their manufacturer-intended scope, requiring the laboratory to independently establish performance characteristics from scratch.
Confusing these two processes — performing only a light verification study on a method that actually requires full validation — is a common and consequential error, since it can leave a laboratory reporting results from a method whose fundamental performance characteristics were never genuinely established.
The Performance Characteristics That Must Be Established
A thorough verification or validation study examines multiple performance characteristics: accuracy (agreement with a known true value), precision (reproducibility of repeated measurements), reportable range, and analytical sensitivity and specificity relevant to the test’s intended clinical use. Skipping any of these dimensions leaves a gap in the laboratory’s understanding of how the method will actually behave across the full range of patient results it will encounter.
For qualitative and semi-quantitative methods, additional considerations such as diagnostic sensitivity, specificity, and agreement with a reference method become central to the validation study — connecting directly to the qualitative quality control principles covered later in this program.
Designing a Defensible Verification or Validation Study
A defensible study uses an adequate number of samples spanning the clinically relevant range, including samples near critical decision points where accuracy matters most, and compares results against an appropriate reference method or established truth. Pre-defined acceptance criteria, set before data collection begins, prevent the temptation to retroactively justify marginal results after the fact.
Documentation of the entire study — protocol, raw data, statistical analysis, and a clear pass/fail conclusion against the pre-defined criteria — must be retained as part of the laboratory’s controlled records, available for review during internal audit or external accreditation assessment.
When Methods Change: Re-Verification and Re-Validation
A significant change to an already-validated method — a new reagent lot with materially different formulation, a software update affecting result calculation, or a change in instrument platform — triggers the need for re-verification or re-validation, proportionate to the scope of the change. Treating every method as permanently validated once, regardless of subsequent changes, is a common gap that undermines the entire purpose of this requirement.
Laboratories that maintain a clear change-control process, flagging when a method modification requires renewed verification, avoid the risk of quietly drifting away from the performance characteristics originally established and documented.
Frequently Asked Questions
Does every new test method require full validation?
No — an already-validated commercial method typically requires verification under local conditions, while laboratory-developed tests, modified methods, or off-label use require full validation.
What happens if a method fails its verification or validation study?
The method should not be used for reportable patient results until the issue is resolved and the study criteria are met, following the laboratory’s nonconforming work and corrective action processes.
Does a reagent lot change ever require re-verification?
It can, particularly if the new lot has a materially different formulation or the laboratory’s ongoing quality control data suggests a meaningful performance shift compared to the previous lot.
Key Takeaways
- Verification confirms an already-validated method performs as claimed locally; validation independently establishes performance from scratch for new or modified methods.
- Confusing verification with validation can leave a laboratory reporting results from a method whose true performance was never established.
- A thorough study examines accuracy, precision, reportable range, and analytical sensitivity and specificity relevant to clinical use.
- Pre-defined acceptance criteria, set before data collection, prevent retroactive justification of marginal results.
- Significant method changes — reagent formulation, software updates, platform changes — require proportionate re-verification or re-validation.
- Complete study documentation must be retained as a controlled record, available for internal audit and external assessment review.
Conclusion
Method verification and validation are the evidentiary backbone of every result a laboratory reports. Without this rigorous, documented process, a laboratory is trusting a method’s claimed performance rather than confirming it under its own real-world conditions.
ISO 15189:2022’s requirements here ensure that trust is earned through evidence, not assumed from a manufacturer’s brochure or a colleague’s prior experience with a similar instrument.
Learn how internal quality control sustains this validated performance day to day in the next courses of this ISO 15189:2022 training series.
Source note: this article draws on “Quality Management in Clinical Laboratory Demystified” by Dr. Taleb Chalab Cham, ISO 15189:2022, and widely recognized clinical laboratory quality references including CLSI guidelines, CAP accreditation checklists, and WHO laboratory quality guidance.
