SNOMED CT is the most comprehensive clinical ontology and is also amenable for automated reasoning. However, in order to unleash its full potential for automated reasoning over clinical text, a mechanism to convert clinical terms into SNOMED CT concepts is necessary. In this paper we present, to the best of our knowledge, the first such complete conversion method that is also capable of converting clinical terms into post-coordinated concepts which are not already listed in SNOMED CT. The method does not require any additional manual annotations and learns only from existing SNOMED CT terms paired with their concepts. The method is based on identifying the defining relations of the clinical concept expressed by a clinical term. We evaluate our method on a large-scale using existing data from SNOMED CT as well as on a small-scale using manually annotated dataset of clinical terms found in clinical text.
