Ensuring internal quality control practices in medical Laboratories: IFCC recommendations for practical applications based on ISO 15189:2022.

This document describes the guidance on implementing and monitoring an IQC strategy that fulfills the requirements of the Standard ISO 15189:2022. It also explores the practical application of these principles in daily IQC processes within medical laboratories. The goal is to provide a practical, user-friendly resource that not only explains the Standard's requirements but also equips laboratory professionals with the tools and knowledge needed to enhance diagnostic reliability. To support laboratory professionals in this task, this document follows the structure and content of the ISO 15189:2022 Standard and provides a risk-based approach in consideration of the practical needs for quantitative results. Specific aspects such as the selection and assessment of IQC materials, the definition of control frequency, the definition of acceptable limits, the application of statistical rules, results from different sources comparability and strategies for handling non-conformities, quality indicators and determination of uncertainty of measurement are discussed in depth. Where relevant, excerpts from the ISO 15189:2022 Standard are included, with clarifications and actionable recommendations to facilitate implementation. This document focuses on the crucial role of IQC in the accreditation process, particularly in the identification of risks, their mitigation through corrective actions and the implementation of improvements to prevent errors and control potential risks in the medical laboratory, ensuring patient safety in daily practice.