ISO/IEC 17025 clause 7.2.1: select and verify laboratory methods
Clause 7.2.1 requires appropriate methods and procedures for laboratory activities and, where relevant, uncertainty evaluation and statistical analysis. Before introducing a method, the laboratory must verify that it can perform it properly and achieve the required performance. A method's publication does not demonstrate your laboratory's capability by itself.
What clause 7.2.1 requires in practice
Clause 7.2.1 sets expectations for choosing methods, keeping them in good order and proving the laboratory can use them. Appropriate methods and procedures must be used for all laboratory activities, along with suitable techniques for uncertainty and data analysis. Methods and the supporting instructions, standards and reference data must be current and easy for staff to reach.
The latest valid version is the default, unless there is a good reason otherwise. If a customer has not named a method, the laboratory picks a suitable one and says which. Published standards, reputable technical sources and manufacturers' methods are all acceptable choices, as are laboratory-developed or modified methods under the right controls. Before first use, the laboratory verifies it can reach the performance needed and keeps records; revisions by the issuing body call for repeat verification to the extent needed. Method development is planned and reviewed, and any deviation from a method must be recorded with a sound technical reason, approved internally, and agreed by the customer.
Select a method that answers the customer's question
Where the customer has not specified a method, select an appropriate one and inform the customer. Recognised published methods and other credible technical sources can be useful; laboratory-developed or modified methods are also possible, subject to the relevant requirements. Evaluate the intended sample, range, purpose and performance rather than choosing a method only because equipment is available.
Use the latest valid version unless doing so is inappropriate or impossible. This qualification requires a defensible decision, not automatic permission to use an old edition indefinitely. Keep methods, supporting instructions and relevant reference data current and readily available to personnel.
Add detail where consistent application needs it
A sufficiently clear published method need not be rewritten as an internal procedure merely to create more documentation. Add necessary detail where choices or local arrangements could lead to inconsistent application. Make the relationship between the source method and internal instructions clear so an update does not leave contradictory steps in use.
Demonstrate performance before introduction
Plan verification around the performance required for the method and application. Use suitable evidence from the laboratory's personnel, equipment and conditions. Retain verification records. The standard does not prescribe one universal experiment or sample number for every technique; competent technical judgement must determine what evidence is adequate.
When the issuing body revises a method, repeat verification to the extent necessary. Evaluate the actual changes. A revised calculation or preparation step can need more attention than a purely editorial correction, but the conclusion should be supported rather than assumed.
Control development and deviations
Method development must be planned, assigned to competent personnel and adequately resourced. Review progress to confirm that customer needs are still being met, and approve and authorise changes to the development plan.
A deviation from a method is permitted only when documented, technically justified, authorised and accepted by the customer. Acceptance can be agreed in advance in the contract. These conditions do not remove the separate prohibition on compromising integrity or validity, nor the need to consider validation where a method is modified or used beyond its intended scope.
Why clause 7.2.1 matters to the laboratory
A method is only a recipe until a particular team, with particular equipment and surroundings, has shown it can follow it and reach the quality the customer needs. Skipping that step makes every later result depend on assumption. Verification pays back quickly: it exposes training gaps, equipment limits and unclear instructions before a customer is affected. Keeping versions under control prevents the quieter problem of two staff using different editions of the same method. Customers and regulators often specify methods, so being able to show the version used, and why a deviation was justified, protects the laboratory when a result is challenged and supports a convincing case for the activities it wants recognised.
How to implement clause 7.2.1
Think of verification as a small, planned study with a written conclusion. Involve the analysts who will use the method from the start, since they usually know where the written instructions are ambiguous.
- Decide the performance the application needs before running anything, such as the closeness and consistency of results expected.
- Choose a verification design that fits the technique, using reference materials, known samples or comparison with a trusted result, and set acceptance criteria in advance.
- Run the work with the staff, equipment and conditions that will be used in routine service, not a specially prepared set.
- Record the data, compare it with the criteria and have a competent person sign off the conclusion, including any limits on use.
- Link the verified method to its source document, version and supporting instructions so updates are noticed.
- Define how issuing-body revisions are monitored and how much verification each type of change needs.
- Create a short deviation form that captures the technical reason, the authoriser and the customer's acceptance.
Two illustrative method decisions
A materials laboratory introduces a published test method on newly installed equipment. It checks whether its staff, equipment and conditions achieve the required performance and retains the verification evidence. The equipment supplier's demonstration is considered for what it proves, not treated as automatic verification of the complete laboratory process.
A calibration laboratory receives a revised method with a changed correction calculation. It evaluates the change, updates controlled instructions and verifies the affected performance before use. It does not simply replace the PDF while leaving an old spreadsheet calculation active.
Evidence and common mistakes
Useful evidence connects method selection, current versions, performance requirements, verification results and approved changes. Avoid confusing verification with routine quality-control results alone, treating customer acceptance as technical justification, or extending a method to a new application without evaluating validation requirements.
Frequently asked questions
Must we rewrite every published method as an internal procedure?
No. A clear method that personnel can use consistently need not be duplicated. Add necessary local detail where it supports correct and consistent application.
Does a recognised standard method still need verification?
Yes. The laboratory must demonstrate that it can achieve the required performance before introducing the method and retain records of that verification.
Can we deviate from a method to meet a customer's deadline?
A deviation needs documentation, technical justification, authorisation and customer acceptance, and must not compromise validity or integrity. A deadline alone is not a technical justification.
Turn this requirement into reliable laboratory practice
Sterling can help your team organise method selection and verification around the scope you need. Discuss a proposed method or revision in a laboratory consultation to identify the technical evidence, training and approval steps required.
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.
ISO/IEC 17025 requirements hub · Method requirements overview · Validate intended use · Personnel authorisation