roles concurrently in the system. Because of these omissions and actual or possible redundancies of semantic content, real-world performance of algorithms to infer subsumption or semantic equivalence will be unpredictably imperfect. SNOMED CT validation Using consistent rules is important for the quality of SNOMED CT. To that end, in 2009, a prototype Machine Readable Concept Model (MRCM) was created by the SNOMED CT team. In a follow up work, this model is being revised to utilize SNOMED CT expression constraints. SNOMED CT and other terminologies SNOMED CT and ICD SNOMED CT is a clinical terminology designed to capture and represent patient data for clinical purposes. The International Statistical Classification of Diseases and Related Health Problems (ICD) is an internationally used medical classification system; which is used to assign diagnostic and, in some national modifications, procedural codes in order to produce coded data for statistical analysis, epidemiology, reimbursement and resource allocation. Both systems use standardized definitions and form a common medical language used within electronic health record (EHR) systems. SNOMED CT enables information input into an EHR system during the course of patient care, while ICD facilitates information retrieval, or output, for secondary data purposes. In 2010s, the advantage of SNOMED CT over ICD was the multiple parent hierarchy of SNOMED CT. Since 2020 release of ICD 11, this advantage is less important because ICD-11 foundational level allows an ICD 11 concept to have multiple parents. SNOMED CT and LOINC LOINC is a terminology that contains laboratory tests. Since 2017, SNOMED International started creating terms for LOINC components and created a set of SNOMED CT expressions that capture the meaning of many LOINC terms. SNOMED CT and MedDRA There is overlap between MedDRA and SNOMED CT that is not beneficial for pharmaceutical industry. In 2021, two maps map between SNOMED CT and MedDRA were jointly published by both organizations (from SNOMED CT to MedDRA and from MedDRA to SNOMED CT). Use SNOMED CT is used in a number of different ways, some of which are: It captures clinical information at the level of detail needed for the provision of healthcare Through sharing data it can reduce the need to repeat health history at each new encounter with a healthcare professional Information can be recorded by different people in different locations and combined into simple information views within the patient record Use of a common terminology decreases the potential for differing interpretation