ISO 17025 scope of accreditation: fixed and flexible scopes, and how to write yours

What is an ISO 17025 scope of accreditation?

A laboratory is never accredited in general. The accreditation body grants accreditation for a defined list of laboratory activities, publishes that list alongside the certificate, and assesses the laboratory against it at every surveillance visit and reassessment.

The requirement behind it sits in clause 5, Structural requirements: the laboratory defines and documents the range of laboratory activities for which it claims conformity with ISO/IEC 17025. The body turns the part you apply for, once assessed, into the published scope.

This guide answers one question: what your scope should contain and how to word it. Whether you need accreditation at all is covered in the decision guide for laboratories, and the order of events from application to decision is in the accreditation process guide.

What goes into each line of the schedule

Accreditation bodies set their own schedule layouts, and a calibration schedule looks different from a testing one, but the same building blocks appear.

Each line needs evidence behind it: a verification or validation file, an uncertainty evaluation, authorised staff, traceable equipment and, where a scheme exists, proficiency testing. The detail of that evidence belongs to the guides on method verification and validation, measurement uncertainty and proficiency testing.

Fixed and flexible scopes

A fixed scope lists each method exactly, usually with its version. Any new method, new matrix, wider range or revised standard is an extension: the laboratory applies, the body assesses, and the schedule is reissued before the new activity may be reported as accredited.

A flexible scope describes a boundary rather than a list, for example a technique applied to a defined group of materials, and permits the laboratory to bring new or revised methods inside that boundary itself. The trade is clear: the laboratory gains speed, and in exchange it must run a documented, validated procedure for adding methods, keep a current internal list of what is covered, and show the assessors that each addition was handled correctly.

Whether flexibility is available, in what forms and with what limits, is decided by each accreditation body, not by ISO/IEC 17025. UKAS (in its GEN 4 provisions) and ANAB (in PR 2311, Flexible Scopes) are two bodies that publish rules on it. Read your body's document before you design your scope around it.

For a first accreditation most laboratories are better served by a fixed scope.

What can be left out, and what cannot

ISO/IEC 17025 does not work like a management system certificate where some requirements are declared not applicable. The standard applies to all organisations performing laboratory activities, whatever their size. What you choose is which activities appear on the schedule; for those activities, clauses 4 to 8 apply in full. The one structural choice in the standard itself is in clause 8, where the laboratory runs its management system under Option A or Option B (a system meeting ISO 9001).

• You may leave out activities. Tests you perform rarely, methods still being validated or work nobody asks to be accredited can stay off the application. They remain unaccredited, and reports for them must not suggest otherwise.
• You may not leave out a requirement for an activity you list. If sampling is part of the listed activity, the sampling requirements (7.3) apply. If you issue statements of conformity, the decision rule agreed in contract review (7.1) and the reporting rules (7.8.6) apply.
• Work you send out is not on your scope. Tests carried out for you by another laboratory are externally provided (6.6). Report them as such, and check the provider's own scope before you rely on it.
• Unlisted work cannot borrow the accreditation. Where a report mixes the two, your body's rules on referring to accreditation say how to mark each result.

Sites, shared services and other interfaces

A multi-site laboratory decides which sites go on the schedule and which activities each site performs. Every listed site is assessed, and the assessors will want to see the activities that take place there, not only the head office's records of them. On-site and mobile work at the customer's premises is a location in its own right.

Look also at what sits outside the laboratory but shapes its results: a group function that calibrates your equipment, a central IT team running the laboratory information system, a purchasing department that selects reference materials. These services stay outside the scope, yet the laboratory remains responsible for them under the requirements for externally provided products and services and for control of data and information management (7.11). Assessors follow a result back through them.

How the scope moves assessment effort and cost

The accreditation body plans its assessment from the scope. Each discipline usually calls for a technical assessor with matching expertise, alongside the lead assessor. Each listed method is a candidate for witnessing, and each additional site adds travel and assessment time. A long, varied schedule means more assessors and more days, at the first assessment and at every surveillance visit.

The same logic runs through preparation. Every line on the schedule needs its own validation or verification, uncertainty evaluation and, where available, proficiency testing, and proficiency rounds follow the provider's calendar. A tightly written scope is the most effective lever a laboratory has on both the programme length and the running cost. See the cost guide and the timeline guide for the detail.

Scope mistakes that cost time

• Too wide. Applying for every method on the equipment list, so validation files are thin and the assessment finds gaps across the board.
• Too narrow. Leaving out the one method the main customer or regulator relies on, which forces an extension soon after the grant.
• Ranges beyond the data. Claiming the range printed in the standard instead of the range the laboratory has shown it can achieve.
• Silent deviations. Listing a standard method while the bench procedure differs from it, turning a verification into a validation the laboratory never did.

ISO 17025 scope of accreditation: questions buyers ask