ISO/IEC 17025:2017 for Chemical Testing Labs: Accreditation, Done Properly

Clauses 4.1 (Impartiality) and 4.2 (Confidentiality) require the lab to identify and manage risks to impartiality on an ongoing basis, with documented evidence of the analysis and the controls. Clause 8.5 (Actions to address risks and opportunities) extends the risk-based thinking into operational planning.

Clause 7.2 requires the lab to use appropriate methods and to validate non-standard, lab-developed and modified methods; standard methods are verified for fit-for-purpose in the lab's scope. Validation parameters — specificity, linearity, accuracy, precision (repeatability and intermediate precision), detection and quantitation limits, robustness — must be appropriate to the analytical purpose.

Clause 7.6 requires evaluation of measurement uncertainty for each test method; clause 7.8.6 requires application of a decision rule (e.g. guard-band conformity assessment per ILAC G8) when a statement of conformity is reported. The 2017 revision's addition of decision rules has caught many labs short — reports that previously said "pass" against a specification without considering uncertainty no longer survive assessment, and customers (particularly in pharma, food and regulated environmental work) are now contractually requiring an explicit decision rule.

Clause 6.4 (Equipment) and clause 6.5 (Metrological traceability) require equipment fit for purpose with calibration traceable to SI units through an unbroken chain of comparisons, each with a stated measurement uncertainty. The recurring finding is a calibration certificate from an accredited supplier whose own traceability chain is not actually checked — the lab assumes the upstream accreditation covers it, the assessor demonstrates the chain is broken at a step nobody examined.

Clause 6.2 requires the lab to define competence requirements for each function, authorise personnel against those requirements, and maintain evidence — qualifications, training, experience, demonstrated performance, ongoing monitoring. The technical signatory who releases reports must be authorised against the specific scope of methods and matrices they sign for.

Clause 7.7 requires the lab to monitor the validity of its results through internal QC (control charts, replicate testing, blind samples, retesting of retained items) and through participation in proficiency testing or interlaboratory comparisons where available. The lab must define the frequency and method of monitoring proportionate to risk, and act on outliers — a single unsatisfactory PT result that does not trigger a documented investigation is one of the most common findings, and a pattern of marginal results that have never been trended is treated as a systemic failure.

Clauses 7.9 (Complaints), 7.10 (Nonconforming work) and 8.9 (Management review) close the loop. Complaints must be acknowledged, investigated, responded to in writing where requested, and trended; nonconforming work must be evaluated for significance (does it require recall of issued reports?), corrected, and the underlying cause addressed.