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Semantic Issues

Hospital information systems, electronic patient record systems, health cards (e.g. EHIC) are only a few examples of the continuously increasing exchange of medical data. Therefore, the distinct naming of diagnoses, services and processes is becoming more and more important. The need for semantic interoperability has also increased due to the specialization and distribution of health services. Data from the attending health professional must be  available  to successive health professionals and must be integrated into the respective documentation system.

Within the epSOS project, several aspects had to be taken into account:

  • different local (classification) systems and
  • diversity in languages

The challenges faced were addressed by the two-fold epSOS strategy, which included an immediately implementable approach as well as an exploratory approach towards new, ontology-based technologies. 

epSOS' semantic services utilize the following key components and techniques:

  • CDA's (Clinical Document Architecture) PCC (Patient Care Coordination)
  • epSOS MVC (Master Value Set Catalogue)
  • epSOS MTC (Master Translation/Transcoding Catalogue)
  • epSOS Ontology

Find here the document on Initiates file download"The experience of selecting the code systems for the development of the epSOS Master Value Sets Catalogue"

CDA's PPC in epSOS

Several Work Packages were active in identifying data elements to be presented in three pivot documents. These data elements were mapped onto the PCC sections, using the definition given by both source and target to ensure equivalence. Whenever the PCC did not provide a section equivalent to the definitions given by the epSOS Work Packages, a section and/or an entry was created using the official epSOS object identifier or OID.


The epSOS Master Value Sets Catalogue contains all value sets used within the framework provided by the CDA and used within the epSOS system. The value sets originate from the following well-established code systems: SNOMED CT, ICD-9, ICD-10, LOINC, ATC, HL7 etc. The epSOS MVC is provided as an Excel file.


The basis for the epSOS MTC is the epSOS MVC. The epSOS MTC is formed by adding transcoding and translation columns for each Member State to be filled in by representatives of, or persons/institutions commissioned by, the Member State. 

The epSOS MTC provides the basis for all epSOS translation/transcoding services. All values of the MVC are represented in every language of importance within the epSOS project. The epSOS MTC is provided in an Excel file.

epSOS Ontology

The epSOS Ontology provides a semantic backbone for the epSOS project. It is an ontology coded in OWL DL based on the MVC. The rationale behind the epSOS Ontology is to provide linguistic reference of the terms in the epSOS value sets. Thus, it is a reference ontology aimed at being utilized to unify different terminologies that will be in use in the future. The main objective is to prepare a formal representation of the entities of interest to epSOS and successively provide support and a consistency check to those parties filling in the MTC.