One goal of the Fast Healthcare Interoperability Resources (FHIR) standard is to prevent semantic ambiguities when patient data are electronically exchanged. To assess whether the FHIR specifications live up to this expectation, we examined FHIR’s Condition resource thereby focusing on the resource elements ‘clinical status’ and ‘verification status’ when used in combination. We found that the definitions for these elements, as well as of several of their allowed values, suffer from the following semantic difficulties: the use of disjunctive descriptions, the presence of pseudo-synonyms lacking clear explanation of what distinctions FHIR has in mind, and insufficient discrimination between evidence and what such evidence would be about.