ADT^A08 is the MPI (Master Patient Index) synchronization message. Any time patient demographics change, the registration system sends A08 to ensure every downstream system has current information.
What is ADT^A08?
A08 is a pure demographic update with no clinical event attached. The message carries the complete patient record (not just changed fields). Receiving systems must apply all incoming fields and replace stored data.
- Address or phone number change
- Insurance update — new payer, policy number, or coverage period
- Name change or spelling correction
- Emergency contact update
- MRN merge follow-up after A40
Message Flow
Registration→
ADT^A08→
Integration Engine→
All Subscriber Systems (LabRadiologyPharmacyEHRBilling)
Segments in this Message
Cardinality: [X] optional · {X} repeating · [{X}] optional & repeating
| Segment | Name | Required | Description |
|---|---|---|---|
MSH | Message Header | Required | MSH-9 = ADT^A08^ADT_A08. |
PID | Patient Identification | Required | Complete updated demographics. Always send the full PID — not just changed fields. |
NK1 | Next of Kin | Optional | Send all NK1 records — the full list replaces the stored contact list. |
IN1 | Insurance | Optional | Updated insurance. IN1-3=insurer ID, IN1-9=group number, IN1-35=coverage period. |
HL7 Message Example
MSH|^~&|EPIC|MERCY|LABSYS|MERCY|20240120102530||ADT^A08^ADT_A08|MSG20240120005|P|2.5.1
EVN|A08|20240120102530
PID|1||MRN-78234^^^MERCY^MR||SMITH^JOHN^ROBERT^^MR||19800315|M|||456 OAK AVENUE APT 2B^^CAMBRIDGE^MA^02139^USA^H||617-555-9876^PRN^PH
NK1|1|SMITH^JANE^MARY^^MRS|SPO^Spouse^HL70063|456 OAK AVENUE^^CAMBRIDGE^MA^02139|617-555-1234^PRN^PH
IN1|1|PPO^Preferred Provider^HL70072|BCBS-MA^Blue Cross Blue Shield MA||||||20240101|20241231|||SMITH^JOHN^ROBERT^^MR|18|19800315FHIR Mapping
| Segment | FHIR |
|---|---|
| PID | Patient (PUT — full replacement) |
| IN1 | Coverage resource |
| NK1 | Patient.contact[] |
Common Errors & Pitfalls
- Partial updates — always send the complete PID, not just changed fields.
- IN1 missing on insurance change — without IN1, many systems won’t update insurance.
- NK1 not complete — send all contacts; the list replaces, not appends.
Vorro Integration Tip
Configure Vorro's field-level diff engine to compare incoming A08 demographics and send targeted updates only to systems that hold the changed fields, reducing unnecessary downstream processing.
