The Referent Tracking paradigm which advocates the use of instance unique identifiers to refer to the entities comprising the subject matter of patient health records promises many benefits to those who use health record data to improve patient care. To further the adoption of the paradigm we provide an illustration of how data from an EHR application needs to be decomposed to make it accord with the tenets of Referent Tracking. We describe the ontological principles on which this decomposition is based in order to allow integration efforts to be applied to other EHR applications by interested parties. We find that an ordinary statement from an EHR reveals a surprising amount of “hidden ” data that is revealed by its decomposition according...