Harmonization of measurement units: mission impossible or ethical imperative?

Harmonization initiatives in laboratory medicine have a long history. Nevertheless, despite substantial efforts by international federations, scientific societies, and expert working groups, their implementation and widespread adoption remain incomplete, with many initiatives still at a relatively early stage of development. More recently, several initiatives have sought to identify scientifically sound yet pragmatic approaches to the harmonization of measurement units. To contribute to this debate, we invited experts from different disciplines of laboratory medicine, as well as a clinician, to provide their perspectives on the challenges, opportunities, and priorities for achieving greater harmonization. This Forum offers a unique opportunity to assess the current state of the art across multiple areas of laboratory medicine, including clinical chemistry, immunoassays, hematology, coagulation, molecular diagnostics, and serology. The contributions presented herein aim not only to highlight discipline-specific challenges but also to identify common principles and practical strategies that may guide future harmonization efforts. Although this paper does not propose a definitive roadmap for the harmonization of measurement units, its ultimate goal is to stimulate informed discussion and present a comprehensive spectrum of perspectives to international federations, national societies, regulatory authorities, and scientific journals. By doing so, it aims to support the identification of the most effective strategies for achieving greater consistency, comparability, and harmonization of laboratory reporting units worldwide.