HL7 Cardinality

Cardinality defines how many times an element must/may appear in a HL7 message. Represented as minimum and maximum instance counts, e.g., 0-to-n or 1-to-1. Also see What is Cardinality in HL7?

Field or Segment Rule Cardinality
Patient address field (PID-11) optional and repeating 0 to n
Patient primary language field (PID-15) optional and non-repeating 0 to 1
Patient class field (PV1-2) required and non-repeating 1 to 1
The Patient Identification (PID) segment in the Patient Admission message (ADT-A01) required and non-repeating 1 to 1