Individual Healthcare Identifier (IHI) format

Format and Luhn checks applied to 16-digit IHIs in PID-3.

The IHI is the national patient identifier issued by the Healthcare Identifiers Service. In HL7 v2 it appears in PID-3 with identifier type NI and assigning authority AUSHIC.

The checks

1. Exactly 16 digits.
2. Prefix 800360 (HPI-I uses 800361, HPI-O 800362).
3. The final digit is a Luhn (mod-10) check digit over the whole number.

These checks prove only that the number is well-formed; they cannot tell you the IHI is active or belongs to the patient named. That requires an HI Service lookup, which this page deliberately does not perform.

Synthetic example that passes: 8003605247640499.

See it fire on a mangled sample