description: |-
  Patient's "public" ID, as used and shown on the EPD patient page. Not necessarily unique,
  and not necessarily present; 0 indicates no patid is known or this EPD does not use public IDs.
  
  The primary purpose of this field is to show it to medical professionals working at this practice
  who can use it to search for this dossier and is a way to communicate without sharing privacy-sensitive
  details.
  
  If this isn't present, the value in `patUnid` is the public ID (i.e. there is no difference).
type: string
example: P000123