ISO/IEC 17025 clause 7.2.2: validate methods for their intended use
Clause 7.2.2 requires validation of non-standard methods, laboratory-developed methods and standard methods modified or used outside their intended scope. Validation must be extensive enough for the application. The central decision is whether the demonstrated performance is suitable for the intended use and the customer's requirements.
What clause 7.2.2 requires in practice
Clause 7.2.2 deals with methods where published evidence of performance is not enough. Validation is needed whenever the method is not a published standard one, was developed in the laboratory, or is a standard method stretched beyond its intended scope or altered in some way. The extent should be as wide as the application demands, and it may reach back to sampling, handling and transport.
The standard lists techniques that can be combined: checking bias and precision with reference materials, assessing influencing factors, varying controlled parameters to test robustness, comparing with other validated methods, interlaboratory comparison, and estimating uncertainty from knowledge of the method. When a validated method is changed, the effect is assessed and revalidation carried out if the original validation is affected. The performance characteristics must be relevant to customers' needs and to specified requirements. Records cover the procedure, the requirements, the characteristics found, the results and a statement on fitness for the intended use.
Define the application before designing the study
Describe what will be measured or tested, the item or matrix, range and purpose. Identify performance characteristics that matter to the decision. Depending on the method, these may include precision, bias, selectivity, detection or quantification capability, robustness, uncertainty or other relevant characteristics. The standard's examples are not a compulsory identical checklist for every method.
Set requirements before evaluating results. A study can produce many measurements without answering whether the method is adequate for the customer's need. Avoid choosing acceptance criteria after seeing the outcome merely to make the method appear satisfactory.
Why clause 7.2.2 matters to the laboratory
Validation is the evidence that a new or altered method does what the customer needs it to do. Without it, a laboratory is asking customers to trust results from a method nobody has tested against their material or purpose. A sound validation lets a laboratory extend its services with confidence, supports a clear scope statement and gives staff a clear account of where the method works and where it does not. It also protects against over-claiming: a conclusion that names the matrix, range and limits stops sales, reporting and technical staff from implying more than the data show. When disputes arise, a well-argued validation record is often the strongest defence the laboratory has.
How to implement clause 7.2.2
Start from the question the customer needs answered, and let that shape the study. Keep the study proportionate: a small extension of a well-understood method needs far less than a new technique, but both need a stated conclusion.
- Write the intended use in a few lines: what is measured, in what item or matrix, over what range and for what decision.
- Choose the performance characteristics that matter to that use and set required values before data are collected.
- Select evidence types that fit, such as reference materials, deliberate variation of key conditions, comparison with another established method or an interlaboratory exercise.
- Assign the work to staff with the right technical competence and give them adequate time and materials.
- Record the plan, raw data, calculations and results in one place, then write a conclusion that states what the method is fit for and what remains unproven.
- Have the conclusion reviewed and approved before the method is used for customer work.
- Define a change trigger so later modifications are assessed against the original study.
Select technically suitable validation evidence
Evidence may come from reference materials, assessment of influencing factors, controlled variation, comparison with another validated method, interlaboratory work or other appropriate approaches. Determine the combination and extent through competent technical judgement. Validation may also need to consider sampling, handling and transport where those stages affect the application.
Use personnel and resources appropriate to the study and retain the basis of the evaluation. A supplier's application note or another laboratory's work may provide useful background, but it does not automatically demonstrate the fitness of your particular implementation and intended use.
Evaluate changes to an already validated method
When a validated method changes, determine the influence of the change. If it affects the original validation, perform a new validation. The extent should be justified by the technical effect. Do not assume every change requires repeating every experiment, but do not describe a material change as administrative to avoid evaluation.
Connect the decision with controlled method versions, software calculations and personnel authorisation. A valid study loses operational value if staff continue using an earlier procedure or an unapproved modification.
Retain the required validation record
Clause 7.2.2.4 requires records of the validation procedure, specified requirements, determined performance characteristics, obtained results and a conclusion on validity that explains fitness for intended use. A report saying only “validated successfully” does not communicate the scope or limitations of that conclusion.
State where the method is suitable and where further work is needed. The customer-facing description, contract review and laboratory scope should not imply wider capability than the evidence supports.
Two illustrative validation decisions
A chemical testing laboratory extends a method from one material matrix to another. It examines relevant interference and performance requirements for the new matrix rather than relying on the original study unchanged. The validation conclusion specifies the new application actually supported.
A materials laboratory modifies a preparation stage to improve throughput. It assesses the effect on the original validation and performs the necessary new validation before releasing the revised method. Faster processing is a potential benefit, but it does not establish equivalent technical performance.
Common mistakes
Avoid copying a validation template with irrelevant characteristics, omitting the intended-use conclusion, or treating equipment calibration as method validation. Also distinguish validation from routine monitoring under clause 7.7: continuing checks help confirm control but do not replace an adequate initial fitness-for-use demonstration.
Frequently asked questions
Does every standard method require full validation by our laboratory?
An unmodified standard method within its intended scope needs laboratory verification. Validation is required for the categories specified in clause 7.2.2, including modified or extended standard methods.
Must a changed method repeat the entire original validation study?
Evaluate the change's influence. Where it affects the original validation, new validation is required to an extent appropriate to the intended application and technical effect.
What is the most important conclusion in a validation report?
The report must explain fitness for the intended use, supported by requirements, performance characteristics and results. A generic pass statement without scope or limitations is inadequate.
Turn this requirement into reliable laboratory practice
Ask Sterling to help structure the validation work and evidence for a method you intend to introduce or extend. A free consultation can clarify the implementation and learning needs while your authorised technical specialists retain responsibility for study design and conclusions.
Build the team's understanding through Method Validation and Verification (ISO/IEC 17025:2017). Discuss the relevant scope, employee learning and agreed access to Effivity ISO & GRC automation software with Sterling; laboratory technical decisions remain with competent, authorised personnel.
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