The Impact of ISO 15189 Laboratory Accreditation on Diagnostic Quality and Patient Care Outcomes: A Systematic Review

Abstract

Background: The medical laboratory produces information that is the basis for the vast majority of clinical decisions, but the laboratory testing process can be flawed at every stage. The international standard for quality and competence in medical laboratories, ISO 15189, has emerged as the world's main laboratory accreditation standard. Despite ISO 15189 accreditation being broadly used, the empirical evidence of measurable improvements in diagnostic quality and patient outcomes is fragmented in heterogeneous literature from high-, middle- and low-income settings. Objective: To gather existing evidence of the relationship between ISO 15189 accreditation and patient care results, as well as diagnostic accuracy and error reduction. Methods: A narrative systematic review of peer-reviewed literature on the ISO 15189 accreditation, external quality assessment, total testing process errors and laboratory process improvement methodologies. 21 sources were included that fulfilled the relevance and verifiability criteria, and they were synthesized thematically. Results: Accreditation and the elements of accreditation, external quality assessment, structured error monitoring, and continuous improvement systems were consistently linked to enhanced analytical reliability, lower pre-analytical error rates, and better organizational quality culture in the various contexts, but the evidence on direct, causally attributable improvements in patient-level clinical outcomes was comparatively limited and methodologically heterogeneous. Conclusion: ISO 15189 accreditation is a legitimate structural proxy for laboratory quality, but it is not the accreditation itself that directly affects patient outcomes, but rather implementation fidelity, resource context, and associated quality systems.

Keywords: ISO 15189 accreditation, Medical laboratory quality, Lab accreditation, Diagnostic accuracy, Quality management systems.