How are observations about entities made while still retaining patient link? There is an extension: focal:subject extension-observation-focal-subject.html This is described in the .subject definition. So can describe the device i.e. implantable device as focal subject of the subject. Also as noted in .subject definition "However, the distinction between the patient's own value for an observation versus that of the fetus, or the donor or blood product unit, etc., are often specified in the observation code." Motion to indicate there is a construct to differentiate focus vs. observation.subject. We will update the text to clarify when to use focal subjet extension vs. the observation.subject. The question whether the extension should become part of core is part of a zulip discussion and would be addressed in a separate tracker.