This code system http://terminology.hl7.org/CodeSystem/med-admin-perform-function defines the following codes:
Code | Display | Definition |
performer | Performer | A person, non-person living subject, organization or device that who actually and principally carries out the action |
verifier | Verifier | A person who verifies the correctness and appropriateness of the service (plan, order, event, etc.) and hence takes on accountability. |
witness | Witness | A person witnessing the action happening without doing anything. A witness is not necessarily aware, much less approves of anything stated in the service event. Example for a witness is students watching an operation or an advanced directive witness. |