The post-analytical phase of laboratory testing is crucial for maximizing the quality and effectiveness of laboratory information. This phase, which includes data reporting, interpretation, and appropriate action, is often overlooked but is essential for improving patient outcomes. The harmonization of this phase is complex due to the involvement of various stakeholders, including laboratorians, physicians, IT specialists, and patients, each speaking different languages. Recent interest in integrated diagnostics, which combines imaging, pathology, and laboratory tests with advanced IT, highlights the need for a common reporting system that integrates text, images, and molecular data to enhance decision-making and care quality. Key components of a well-harmonized post-analytical phase include standardized laboratory reports, measurement uncertainty (MU) reporting, reference intervals (RIs) and decision limits (DLs), reference change values (RCVs), critical results reporting, and interpretative comments. These elements ensure that laboratory results are accurate, clear, and actionable for both clinicians and patients. Standardization of terminology, units, and reporting formats is essential to improve communication and reduce errors. Additionally, the integration of AI and machine learning can enhance data aggregation, interpretation, and reporting, but only if the underlying data are standardized and harmonized. The article emphasizes the importance of harmonizing the post-analytical phase to improve patient care and reduce diagnostic errors. It calls for increased efforts from laboratory professionals, scientific societies, and regulatory bodies to develop and implement guidelines and recommendations to enhance the quality and effectiveness of laboratory reports and their communication to users.The post-analytical phase of laboratory testing is crucial for maximizing the quality and effectiveness of laboratory information. This phase, which includes data reporting, interpretation, and appropriate action, is often overlooked but is essential for improving patient outcomes. The harmonization of this phase is complex due to the involvement of various stakeholders, including laboratorians, physicians, IT specialists, and patients, each speaking different languages. Recent interest in integrated diagnostics, which combines imaging, pathology, and laboratory tests with advanced IT, highlights the need for a common reporting system that integrates text, images, and molecular data to enhance decision-making and care quality. Key components of a well-harmonized post-analytical phase include standardized laboratory reports, measurement uncertainty (MU) reporting, reference intervals (RIs) and decision limits (DLs), reference change values (RCVs), critical results reporting, and interpretative comments. These elements ensure that laboratory results are accurate, clear, and actionable for both clinicians and patients. Standardization of terminology, units, and reporting formats is essential to improve communication and reduce errors. Additionally, the integration of AI and machine learning can enhance data aggregation, interpretation, and reporting, but only if the underlying data are standardized and harmonized. The article emphasizes the importance of harmonizing the post-analytical phase to improve patient care and reduce diagnostic errors. It calls for increased efforts from laboratory professionals, scientific societies, and regulatory bodies to develop and implement guidelines and recommendations to enhance the quality and effectiveness of laboratory reports and their communication to users.