^A28
ADT^A28 — Add Person Information
Sent to add a new person record to a Master Patient Index (MPI) or downstream system without creating a visit or encounter. It carries person-level demographic information only — there is no PV1 visit context.
When Is This Sent?
When a new patient is registered in the MPI for the first time, outside of any specific encounter. Common in enterprise MPI systems where patient demographics are maintained separately from visit records.
Real-World Usage
A28 is used by enterprise MPI and HIE systems to propagate new patient registrations. A new patient registered at one facility sends an A28 to the central MPI, which then distributes the identity to all connected systems. Unlike A01/A04 (which create visits), A28 creates only the patient identity record. Systems that rely exclusively on A01 for patient registration will not see patients until their first visit.
Message Structure
Segment names link to their field-level reference pages.
| # | Segment | Purpose in this message | Req | Repeat |
|---|---|---|---|---|
| 1 | MSH | Message header with ADT^A28 in MSH.9 | R | — |
| 2 | EVN | Event type with A28 trigger | R | — |
| 3 | PID | Full patient demographics to be added to the MPI | R | — |
| 4 | PD1 | Additional demographics including primary care provider | O | — |
| 5 | NK1 | Next of kin and emergency contacts | O | Yes |
| 6 | AL1 | Known allergies | O | Yes |
| 7 | IN1 | Insurance information | O | Yes |
Example Message
Realistic example with fake patient data. Paste into the HL7 Message Viewer to explore interactively.
1MSH||^~\&|ENTERPRISE_MPI|HEALTH_SYSTEM|MIRTH_PROD|EPIC|20260310080000||ADT^A28^ADT_A28|MSG00090|P|2.5.1 2EVN||A28|20260310080000 3PID||1||567890^^^HOSP_A^MR~ENTID123^^^ENTERPRISE^PI||Davis^Margaret^E||19450318|F|||300 Pine St^^Springfield^IL^62705^US^H||2175553456^PRN^PH
Troubleshooting Scenarios
New patient not appearing in EHR after MPI registration
Cause
EHR is not subscribed to A28 events, or does not support A28 without a PV1 segment.
Fix
Check whether the EHR requires PV1 even for person-only messages. Some EHRs will not create a patient record without visit context — in that case, the MPI must either include a dummy PV1 or use a different mechanism such as A31 with a flag.
Common Confusions
ADT^A28 (Add Person) vs ADT^A01 (Admit). A28 creates only a person record in the MPI — no encounter is created. A01 creates a full visit/encounter. In systems that conflate person and encounter records, A28 may be processed identically to A01, but they are semantically different.
Related Message Types
Segment Reference
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