My project has unique record ids that are assign to participants at enrollment into the study. The enrolled participants also have unique clinical ids used at their respective facilities. 

These clinical ids are captured in redcap as a PHI. My problem arises where one participants is enrolled twice into the study hence two different record ids having identical clinical ids (PHI) which is not suppose to be the case. Every unique record id should have a unique clinical id. Is there a possibility of customizing the clinical ids so that one unique clinical id can only be entered once?