7.2 Selection, verification and validation of methods

The laboratory must use appropriate methods for all activities and, where applicable, for evaluating measurement uncertainty and using statistical techniques for data analysis. Preference goes to methods published in international, regional or national standards; where a customer does not specify a method, the lab selects an appropriate one and informs the customer.

Two distinct concepts sit inside 7.2 and are frequently confused in practice:

• Method verification: confirming that the laboratory can properly operate a standard method before using it, obtaining the performance the method's originator claims. This applies to standard methods being brought into use for the first time.
• Method validation: required for non-standard methods, laboratory-developed methods, standard methods used outside their intended scope, and amplifications or modifications of standard methods. Validation must be as extensive as needed to meet the needs of the given application, and the laboratory has to record the validation results, the procedure used, and a statement on the method's fitness for the intended use.

Where the customer's requirements change, or the method itself is revised, the lab must repeat the validation work needed to confirm the method still meets the requirement.

7.3 Sampling

Where sampling is part of the laboratory's scope of activity, it must be carried out according to a sampling plan and method that address the factors to be controlled to ensure the validity of subsequent test or calibration results. The sampling method should address selection, the sampling plan, drawing and preparation of samples from a substance, material or product to yield the required information.

The laboratory is required to record the sampling data that forms part of the test or calibration carried out, including any deviation from the sampling method, and — where relevant, and agreed with the customer — a statistical basis for the sampling procedure.

7.4 Handling of test or calibration items

The laboratory must have a procedure for the transportation, receipt, handling, protection, storage, retention and disposal or return of items, including all provisions necessary to protect the integrity of the item and the interests of the lab and the customer. This includes recording any deviation from specified conditions on receipt, using a system to identify items unambiguously throughout their life in the laboratory (so they are never confused with other items), and recording anomalies noted at intake before work proceeds.

7.5 Technical records

Technical records for each activity must contain the results, report, sufficient information to facilitate identification of factors affecting the result and its uncertainty, and enough detail to allow, as far as practicable, the activity to be repeated under conditions as close as possible to the original. Records must include the identity of personnel performing each activity and, where relevant, checking results.

Original observations, data and calculations must be recorded at the time they are made and be identifiable to the specific task. Amendments to records must not obscure the original entry, and the reason for the change should be recorded where practicable — a requirement that applies equally to paper records and to electronic ones held in a laboratory information management system.

7.6 Evaluation of measurement uncertainty

Laboratories must identify the contributors to measurement uncertainty and make a reasonable estimation, using an appropriate method of analysis, ensuring that the reporting of the result is consistent with its intended use. This obligation applies to calibration and, for testing, to a somewhat more nuanced degree — testing laboratories must at minimum attempt to identify all contributors and make a reasonable estimation, even where a full formal budget is not always practical for every method.

This is one of the areas most frequently cited in audit findings, because it sits at the intersection of statistics, metrology and day-to-day practicality. Common weaknesses include uncertainty budgets that are copied from a method's original validation study without being re-evaluated for the laboratory's own equipment and conditions, budgets that omit significant contributors (such as sample inhomogeneity or operator effects), and a failure to demonstrate that the stated uncertainty is actually consistent with what proficiency testing or intermediate checks show in practice.

7.7 Ensuring the validity of results

The laboratory must have a procedure for monitoring the validity of its results, with monitoring planned, reviewed and, where applicable, including: use of reference materials or quality control materials, use of alternative instrumentation, functional checks of measuring equipment, use of check or working standards with control charts, intermediate checks, replicate tests or calibrations, retesting of retained items, correlation of results for different characteristics of an item, and review of reported results.

Participation in interlaboratory comparisons and proficiency testing is a specifically required part of this monitoring wherever it is available and appropriate. The laboratory has to analyze the resulting data against pre-defined criteria and use the outcome to control and, where needed, improve its activities. Where monitoring data shows results falling outside pre-defined criteria, planned action must be taken to correct the problem and prevent incorrect results from being reported.

7.8 Reporting of results

Results must be reviewed and authorized before release, and reported accurately, clearly, unambiguously and objectively, normally in a test report or calibration certificate. The standard sets out common content requirements (a title, the laboratory's name and address, unique identification, identification of the method used, a description and identification of the item, results with units of measurement, and authorization details, among others) plus additional requirements specific to test reports, calibration certificates, and statements of conformity.

Where a statement of conformity to a specification is reported, the laboratory must identify which decision rule was applied — unless the decision rule is inherent in the requested specification or standard itself. Opinions and interpretations included in a report must be clearly identified as such and, where applicable, be justified and based on the results obtained.

7.9 Complaints and 7.10 Nonconforming work

Clause 7.9 requires a documented process for receiving, evaluating and making decisions on complaints, including acknowledging receipt, tracking progress and outcomes, and ensuring impartiality in who is involved in handling and resolving each complaint. Clause 7.10 requires a procedure to be implemented whenever any aspect of the laboratory's work, or the results, does not conform to its own procedures or the agreed requirements of the customer — covering responsibilities and authorities for managing the nonconforming work, evaluation of its significance, a decision on acceptability, notification of the customer where needed, and defined responsibility for authorizing resumption of work.

7.11 Control of data and information management

Where the laboratory uses a laboratory information management system (LIMS) or other computerized system for the collection, processing, recording, reporting, storage or retrieval of data, that system must be validated for functionality before introduction, and data must be protected from unauthorized access and safeguarded against tampering and loss. The system also needs to be operated in an environment complying with any supplier-specified or laboratory-defined requirements, and the laboratory must maintain the integrity of calculations and data transfers in an appropriate and systematic manner.

Common audit findings on clause 7

Because clause 7 covers the actual technical operation of the laboratory, it tends to generate the largest share of nonconformities during accreditation and surveillance assessments. Recurring themes include:

• 7.2 — Validation records that don't show fitness for purpose: a non-standard or modified method is in routine use, but the validation record does not clearly state the parameters evaluated or conclude the method is fit for its intended application.
• 7.5 — Records that can't reconstruct the work: a technical record exists, but it lacks enough detail — raw data, calculation steps, or the identity of who performed each step — to allow the activity to be traced back and, as far as practicable, repeated.
• 7.6 — Inadequate measurement uncertainty evaluation: uncertainty budgets are reused from a method's original source without being re-evaluated for the laboratory's own equipment, environment and operators, or significant contributors are omitted altogether.
• 7.7 — Insufficient participation in proficiency testing: PT or interlaboratory comparison participation has lapsed, is missing for a method with an available scheme, or an unsatisfactory result was not followed by a documented investigation.
• 7.8 — Statements of conformity without a defined decision rule: a report states pass/fail against a specification, but the report does not identify which decision rule was applied to reach that conclusion.

Practical impact for the laboratory

Because clause 7 covers the largest and most technical part of the standard, it is also the part with the largest ongoing documentation burden: contract reviews, method files, sampling records, technical records, uncertainty budgets, PT results and reports all accumulate continuously, across every method and every job the laboratory runs. Labs that struggle most under clause 7 are usually not the ones lacking technical competence — they are the ones where evidence of that competence is scattered across spreadsheets, paper files and individual analysts' notebooks, making it hard to retrieve consistently when an assessor, or an internal auditor, asks for it.

This is precisely where a tool like IgeraIndustria is useful in practice: it lets lab staff and auditors ask a direct question — which uncertainty budgets are overdue for review, what was the outcome of the last proficiency testing round for a given method, where is the validation record for a specific test — and get an answer that cites the exact source document within the lab's own quality management system, rather than requiring a manual search across files.

Frequently asked questions about ISO 17025 clause 7

What is the difference between method verification and method validation under clause 7.2?

Verification confirms that the laboratory can properly perform a standard, published method and achieve the performance its originator claims, before using it routinely. Validation is required for non-standard methods, laboratory-developed methods, and standard methods used outside their intended scope or modified — it involves a more extensive assessment of performance characteristics and results in a documented statement of the method's fitness for its intended use.

Do testing laboratories have to calculate a full measurement uncertainty budget for every method?

Clause 7.6 requires laboratories to identify the contributors to measurement uncertainty and make a reasonable estimation, ensuring the reporting of results is consistent with their intended use. For calibration this generally means a rigorous, quantified budget. For testing, the depth of the evaluation can vary by method and application, but the laboratory still has to demonstrate it has identified the relevant contributors and estimated their effect — it cannot simply omit the exercise.

Is participation in proficiency testing mandatory under ISO 17025?

Clause 7.7 requires the laboratory to monitor the validity of its results, and specifically identifies participation in interlaboratory comparisons as part of that monitoring, wherever available and appropriate. Where no proficiency testing scheme exists for a particular method, the laboratory still needs an alternative, documented approach to demonstrating validity — the general obligation to monitor performance under 7.7 does not disappear simply because a formal scheme is unavailable.

What must a test report or calibration certificate include under clause 7.8?

The standard sets out common requirements — including a title, the laboratory's name and address, unique identification, the method used, description and identification of the item, results with units, and details of who authorized the report — plus additional content specific to test reports, calibration certificates, and statements of conformity. Where a statement of conformity is reported, the decision rule applied must be identified, unless it is inherent in the requested specification itself.

How does clause 7 differ from clauses 5 and 6 of ISO 17025?

Clause 5 addresses structural requirements such as the laboratory's legal status, organization and impartiality. Clause 6 covers resource requirements — personnel, facilities, equipment and metrological traceability. Clause 7 addresses process requirements: how the laboratory actually carries out its testing or calibration work, from accepting a request through to reporting the result. Clause 6 largely establishes whether the laboratory has the right resources; clause 7 governs how those resources are used on every job.

What happens if nonconforming work is discovered after a report has already been issued?

Clause 7.10 requires the laboratory to implement a procedure whenever any aspect of its work is found not to conform with its own procedures or agreed customer requirements. This includes evaluating the significance of the nonconformity, deciding on the acceptability of the affected work, and notifying the customer where the nonconformity could affect a report or certificate already issued. The laboratory also needs to define who is responsible for authorizing the resumption of the work once the issue has been addressed.

Does clause 7.11 apply to a simple spreadsheet used for calculations?

Clause 7.11 applies to computerized systems used for the collection, processing, recording, reporting, storage or retrieval of data, which in practice includes spreadsheets used for calculations feeding into results, not only a dedicated LIMS. The requirement is proportionate to the system's role and risk, but the laboratory still needs to demonstrate the system is validated for its intended function, protected from unauthorized changes, and that calculations and data transfers maintain integrity.

Expert ISO 17025 · Updated 2026-09-25