Every Member States shall make, if necessary, transcoding of national code systems to ensure the correct transmission of patient data to another Member State. Member States should come to an agreement on how to develop, publish and maintain a master catalogue for cross-border health data exchange scenarios. Relevant Value set Catalogues should be easily available for implementers. Ideally, Value set Catalogues should form a network of EU Value set Catalogues accessible and interoperable across Europe with a harmonised and sustainable maintenance process.