Information exchange at the level of semantic interoperability requires that information models and clinical terminologies work well together. In HL7 FHIR resources, terminology binding to standard terminologies such as SNOMED CT are suggested, and even though most are suggestions rather than rules, they still must reflect the clinical domain accurately. In this study, we suggest a method for empirically evaluating whether a terminology binding represents the value sets used in practice. We evaluated the terminology binding associated with the MedicationRequest.reasonCode using the Danish national indication value set which we mapped to SNOMED CT. We found two problems with the terminology binding, namely, that the reason for prophylactic treatment and that medication given as part of a procedure, but not related to the patients' problems per se could not be expressed within the boundary of HL7 FHIR's example terminology binding. Future work will include showing how more complex terminology binding issues could be informed by looking at value sets in use.