Role of labs in POC testing under ISO 15189:2022 and EQA for testing accuracyRole of labs in POC testing under ISO 15189:2022 and EQA for testing accuracy

In December 2022, the International Standards Organization (ISO) released a new revision of its standard for medical testing laboratories, ISO 15189. Based on input from a wide range of professionals, academics, and government advisors from around the world, the changes in ISO 15189:2022 address the advent of new technologies, evolving laboratory structures, and advancements in the practice of patient care such as point-of-care (POC) testing.

It places heavy emphasis on patient safety and satisfaction while allowing more flexibility in terms of laboratory structure. By being less prescriptive about how requirements should be implemented, this revised standard allows labs to implement practices that work for their unique situation while continuing to keep patients safe.

Maintaining patient safety in point-of-care testing

As testing strategies have become more reliant on lower-complexity analytical tools, testing can move closer to patients providing results faster and making testing more convenient. Staff whose roles did not previously include diagnostic testing can help address global laboratory staffing shortages by being trained to perform tests at the point of care but need additional training and ongoing assessment to ensure high-quality of test results.

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Inaccurate diagnostic test results have a ripple effect: they burden medical systems with unnecessary procedures, erode patient trust, pollute data used to determine health policy, and – worst of all – result in patient harm. Currently, diagnostic errors contribute to approximately 10 per cent of preventable patient deaths, and medical reviews suggest that they account for six to 17 per cent of adverse events in hospitals.

To reduce the risk to patients as less specialised staff begin performing diagnostic testing, there is a strong need for quality management, oversight, and external quality analysis (EQA). Indeed, ISO 15189:2022 requires laboratories and point-of-care testing locations to subscribe to an EQA programme for each kind of testing that each site provides.

Even if a point-of-care testing site is overseen by a main diagnostic lab, each point-of-care testing site needs to subscribe to its own EQA programmes to ensure a high quality of testing at each location. The relationship between each point of care testing service location and the lab overseeing it must be elucidated and documented as part of adherence to the standard.

EQA as a tool for maintaining testing accuracy

While EQA is a necessary step for a lab to become accredited to the ISO 15189 standard, a subscription to an EQA programme can provide value beyond simply ensuring labs meet a minimum quality bar. It’s important to recognise EQA as a tool for continual improvement and education of staff and refinement of procedure and quality practice. EQA providers have a unique opportunity to be a part of improving patient safety by helping labs find sources of error and working with the lab to remediate them. Some EQA providers – like Canadian Microbiology Proficiency Testing (CMPT) – expand the scope of evaluation to the pre and post-analytical phase by offering simulated products that mimic real samples and providing critiques on not only the results of the test but on the reporting of those results.

The global COVID-19 pandemic helped highlight the many benefits – and challenges – of bringing testing closer to the patient. In Canada and throughout the world, point-of-care testing locations for COVID-19 enabled health authorities to handle the greatly expanded volume of tests required to maintain population health and safety. Tests were simple to use but were often performed by less-experienced staff who were not as familiar with the intricacies of running and interpreting Rapid Antigen Diagnostics (RADs) or Nucleic Acid Amplification Tests (NAATs). It is worth mentioning, however, that even experienced staff can make mistakes or have misconceptions about a particular test.

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At CMPT, our COVID-19 proficiency testing programme was launched in March 2021. The programme was designed for RAD and NAAT testing methods and included six shipments per year, each containing four samples which either contained or did not contain the SARS-CoV-2 virus. Importantly, the concentration of the samples was varied to ensure that positive samples might be strong, medium, or weakly positive to simulate varying viral concentrations in a real sample.

While NAAT performance was high from the very beginning, RAD testing performance was initially low at 46 per cent accuracy in 2021. In evaluating this data, CMPT found that for medium positive samples, the accuracy rate was 42 +/- 13 per cent, and that weakly positive bands were largely being reported as negative.

Since CMPT was aware of testing methods being used for its samples, labs using RAD tests were identified and given coaching on how to correctly interpret a medium or weakly positive result. This intervention was near-real time and enabled labs to address the gap in training quickly. As a result, RAD testing accuracy improved rapidly, eventually reaching 93 +/- 7 per cent – roughly equivalent to NAAT accuracy – after eight months.

Total enrolment of labs in our proficiency testing programme for COVID-19 peaked in July 2022 with 110 testing locations, many of which were not testing labs and had not needed to be accredited before. When surveyed, one-third of respondents had never heard of proficiency testing and were not fully aware of the accreditation process and its requirements. Not only does this suggest an explanation as to why some testing sites may have had trouble correctly interpreting the tests, but it also indicates a need for discussion, education, coaching, and mentorship as point-of-care testing in community settings becomes more common.

Point-of-care testing is on the rise for many reasons – staffing shortages, increased testing volume, patients’ desire for convenience – and will likely be a driver of improved population health. But with this large systemic change comes a need for great care as well as increased and continual training and education. ISO 15189:2022’s requirement for testing sites to perform EQA will help ensure patients stay safe, but it is up to EQA providers to ensure their schemes exercise as much of the testing process as possible and that they identify issues and provide educational feedback to their subscribers. As bastions of testing quality, EQA providers are in a unique position to help ensure patient safety.

References available on request.

Dr. Lucy Perrone is a Professor of Laboratory Quality, Dept of Pathology and Laboratory Medicine at the University of British Columbia in Canada.