The PID segment is used by all applications as the primary means of communicating patient identification information. This segment contains permanent patient identifying.

• All possible fields (there are many)

Basic example :

PID|PatientID|Patient Identifier List|Alternate Patient ID - PID|Patient Name

Attention: The PID-2 field was retained for backward compatibility only as of v2.3.1 and was withdrawn and removed from this message structure as of v2.7. It is recommended to use PID-3 - Patient Identifier List for all patient identifiers.

Source : https://v2plus.hl7.org/2021Jan/segment-definition/SCD.html#SCD-33

How is the Patient Identifier List constructed

• [DATA TYPE] CX: Extended Composite ID with Check

12345^^^^PI

In this example:

• CX-1 : 12345 is the value of the identifier itself. [String][Required]
• CX-2 : digits, or digits, exclusive of the identifier in CX-1, calculated by applying an algorithm to all or some of the digits in the number, which may be used to test validity of the non-check-digit identifier. [String] [Opt]
• CX-3 : Code Identifying The Check Digit Scheme Employed [ID][Opt]
• CX-4: Is the assigning authority [HD][Opt]
• CX-5: PI is the identifier type code [ID][Opt]
  • Possible identifiers