From conventional to personalized reference intervals and decision limits: addressing latent errors in the post-post analytical phase

Laboratory errors are an important component of medical errors and are predominantly associated with the extra-analytical phases of the total testing process, particularly the pre-pre-analytical and post-post-analytical phases, which are largely dependent on clinical activities but also require laboratory support. The post-post-analytical phase is the stage in which clinicians interpret patients' laboratory data using population-based reference data, such as population-based reference intervals (popRIs) and population-based decision limits (popDLs), typically provided by the laboratory. To minimize errors in this phase, it is essential that more accurate tools - such as personalized reference intervals (prRIs) and personalized decision limits (prDLs) - are made available to clinicians. However, population-based references are still widely used, whereas their personalized counterparts have not yet been implemented in routine practice. The discrepancy between inadequate population-based references and more appropriate personalized references can introduce systematic yet latent errors in the interpretation of patients' laboratory data, potentially compromising patient safety even when clinicians are highly competent in data interpretation. In this opinion paper, we (1) summarize the limitations of popRIs and popDLs, (2) develop the concept of latent errors, and (3) discuss how personalized RIs and personalized DLs can be used to reduce latent errors and enable more accurate interpretation of patient laboratory data.