ISO 17025 case study: how a calibration and testing laboratory proved its accuracy

The organisation and what it needed

This anonymised account is drawn from Sterling's case studies. The organisation is a laboratory that performs both calibration and testing work for its customers.

Its people were confident in the accuracy of their measurements. The difficulty was not the quality of the work but the lack of evidence behind it. A customer receiving a calibration had to take the laboratory's competence on trust, and trust on its own does not travel far.

The laboratory therefore needed a recognised way to demonstrate that its accuracy was real, repeatable and documented, rather than simply asserted. ISO/IEC 17025, backed by accreditation, was the route it chose.

What was implemented

The laboratory built a management system to ISO/IEC 17025. The account singles out three technical areas where the system brought rigour to existing practice.

How it calibrates

Calibration work was placed under the discipline of the standard, so that the way each calibration is carried out became defined and consistent instead of depending on individual habit.

How it manages reference standards

The reference standards on which every calibration depends were brought under structured management, giving the laboratory control over the instruments that anchor its measurements.

How it analyses measurement uncertainty

Measurement uncertainty analysis was made systematic, so that the confidence attached to a result could be stated and defended rather than assumed.

Alongside these, the laboratory documented the traceability of its measurements and went through accreditation.

What changed

According to the account, the new rigour made the laboratory's services more reliable. Documented traceability, together with accreditation, turned it into a calibration provider that customers trust, and its results are now accepted internationally.

Its laboratory manager said that accreditation had been a turning point for the business.

About ISO/IEC 17025

ISO/IEC 17025 sets out what testing and calibration laboratories need in order to operate competently, impartially and consistently, so that the results they issue can be relied upon. The current edition is ISO/IEC 17025:2017, which ISO confirmed at its 2023 review; there is no amendment and no transition under way.

It is an accreditation standard, not a certification standard. An accreditation body working to ISO/IEC 17011 assesses the laboratory, with assessors who watch calibrations or tests being carried out and examine the evidence behind them. If satisfied, it grants accreditation for a published scope of activities, methods, ranges and sites. International acceptance of accredited results now rests on the Global ACI MRA, which from 1 January 2026 replaced the ILAC MRA when ILAC and IAF combined.

The three areas highlighted in this case sit mainly in the resource and process clauses of the standard, summarised below.

How Sterling runs a programme like this

What follows describes how Sterling generally approaches an ISO/IEC 17025 engagement; it is not a description of this particular laboratory's project.

Laboratories choose one of two alternative support levels. With Design™, Sterling develops the system and the laboratory implements it under expert advice and supervision. With Drive™, Sterling designs and builds the system under the laboratory's approval, as a fully managed service. Either way, the work typically runs from scoping and a gap analysis against clauses 4 to 8, through method validation, uncertainty evaluation and traceability, to an internal audit and management review before the accreditation body is approached.

Effivity, used in 50+ countries, is included with the engagement at no additional cost, so controlled procedures, records, corrective actions and audit findings sit in one place from the start. The engagement also covers internal auditor training for your audit team, as applicable to your standard. After accreditation, Sustain™ supports the laboratory through surveillance and reassessment.

ISO/IEC 17025 for calibration and testing laboratories: questions buyers ask