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Laboratory processes and procedures

In the latest of our ISO 15189:2022 series of articles, Dr Mairiead MacLennan looks at some pertinent questions.

The introduction of the revised version of ISO 15189:2022 Medical Laboratories – Requirements for Quality and Competence will have a three-year phasing process for most laboratories. Gap analysis documents have been prepared and are available on the UKAS website; meetings will be planned and arranged for communication flow between UKAS and laboratory services. Technical Assessors are currently undergoing training in the interpretation and application during assessments.

Extending scope of accreditation

A particular area of concern for laboratories is applying to extend their scope of accreditation. Whilst some departments are entirely comfortable with the process, others are confused by what the assessor is looking for. Loss of experienced staff and carrying a high level of staff in training may also compromise their ability to appropriately perform evaluation, validation, verification and ongoing fitness-for-purpose confirmation.

As with the 2012 standard, there is no standard methodology or description given for the version 2022. For some this would have made sense, but to enable equitable application across disciplines, this could not be prescriptively described in the document.

It is helpful to start by reading section three, which clarifies all definitions.

However, if read carefully, there is a template that can be applied to both verification and validation, described in ISO 15189:2022.

There is a clear difference between verification and validation, the latter being wider in scope and requiring a more detailed experimental design, because the work is novel. Verification is performed on previously validated procedures. Both however, must have acceptance criteria, set by the laboratory, that reflect a set of requirements that the new process must meet, before it will be implemented. Setting appropriate acceptance criteria is central to both verifications and validations, as it is against these criteria that the described outcomes will be  assessed as having been met.

ISO 15189:2022 section 7.3 Examination processes states: “The laboratory shall select and use examination methods which have been validated for their intended use to assure the clinical accuracy of the examination for patient testing.”

These must be verified before use. Section 7.3.3 a–e refer to in-house methods, validated methods used outside of their scope and validated methods subsequently modified, all of which require validation.

In both, the use case must be stated as a performance benchmark. The need for the new procedure or process must be described and patient need and/or service requirements must be clear.

The documentation of any verification must also demonstrate “that the required performance, as specified by the manufacturer or method, can be achieved”, which is frequently overlooked in documentation.

The results must be capable of reflecting the clinical application. There is little point in securing a test with a limit of detection of the target of say, 15 mmol/L in serum stated in the Information for Users (IFU) if the diseased state is confirmed at 10 mmol/L in plasma, in peer-reviewed documents. Why not secure a test that meets the users’ needs?

The experimental design, the results of the experiment and the interpretation of the data analysis must be documented, reflecting the content of the IFU accompanying the assay. All of which must reflect the successful attainment of the validation of the procedure by the manufacturer, found within that document. If the validation is not readily available, it must be sought from the method developers.

What to include

Reflecting upon this, if a department is unclear as to what to include, the formal structure of: introduction, aims and objectives, materials and methods, results and discussion followed by conclusion and references can be considered. “Introduction” is the rationale for introduction of the procedure, (use case and clinical application) “aims and objectives” are the acceptance criteria, “materials and methods” are the assay, platform, operators, project leaders etc. The “results” section speaks for itself, then “discussion” of results achieved and the impact on the patient. It is important to clarify unexpected results. The document need not be a tome, but must meet all the statements of section 7.3.2 of the updated standard.

Internal Quality Control (IQC) External Quality Assurance (EQA) Measurement Uncertainty (MU) must all be included in the document. All add evidence of the robustness of the laboratory’s ability to achieve the results detailed in the IFU “in their hands” while also demonstrating that the results can be used safely for patient management. The IQC demonstrates repeatability and the EQA reproducibility, demonstrating the “correct results” are consistently achieved. Result output is not safe for patient management if the patient progress and/or treatment being managed is based on the results of tests that do not provide consistent results.

Ongoing fitness for purpose

A key requirement for compliance with ISO 15189:2022 is the confirmation of ongoing fitness for purpose. There are many ways to approach this, however, consideration of the interval between such reviews must capture the risk associated with the procedure/process. There is little point setting a target that is not achievable as this means it is unlikely to be met. If a department has 800 SOPs, it is unrealistic to confirm ongoing fitness for purpose by an individual SOP. In blood sciences this can be done perhaps by methodology or platform, or a combination of both. Likewise in microbiology by bench/similar processes.

Data collated since the time of the last documented confirmation of fitness for purpose provide all requirements for such a review. IQC, IQA, EQA data, changes to SOPs, change controls, audits, UKAS findings and non-conformances raised related to the process, any complaints from users, SMI updates in microbiology, all pulled together in a review or “reverification” will demonstrate that the department has considered the procedure or process and assessed whether it demonstrably continues to meet the needs of clinicians, patients, and therefore, the department.

Readers will note that more often than in the previous version of the standard, it is stated that the impact on the patient must be demonstrated in quality management system (QMS) documents. Understanding such impact, therefore, can start at the verification stage. For staff in training, participating in verifications is an excellent way to introduce them to deeper understanding of the department’s QMS, to the standard, and to the concept of ongoing fitness for purpose. The demonstration of participation in verification is excellent evidence for the Specialist portfolio in all disciplines.  

Dr Mairiead MacLennan is Biomedical Scientist Professional Manager (Quality/Training) / Interim Service Manager Microbiology, NHS Fife

Image credit | iStock

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