Validation of Methods in Medical Laboratories, ISO Standards, CLSI Guidelines, and Recommendations: A Point of View

This note is intended to address the concepts contained in certain requirements of ISO 15189:2022, in comparison with selected regulatory sources and guidelines. ISO 15189 contains two concepts that are often confused: method verification and method validation. Some recent sources provide tools to clearly understand these concepts and put them into practice. These include the CLSI EP49:2025 guideline, the ISO/AWI TS 17849 draft, and the ISO 20916:2019 and ISO 5649:2024 standards. In addition to these, there are the SIPMeL Q21:2024 Recommendations, which combine the requirements of ISO 15189 with useful additions from other ISO and CLSI sources. In this note, the author presents the results of a source analysis that highlights significant lexical and conceptual issues, particularly in CLSI EP49. However, the body of sources currently available provides laboratories and developers of in vitro diagnostic test methods with many tools to achieve the objectives set forth by ISO accreditation requirements and to operate in a manner that benefits patients and physicians who rely on the services of these laboratories. Despite the brevity required by the format of this presentation, it is hoped that the observations set forth here may be discussed, confirmed, or even refuted by other viewpoints.