| HL7v2 Message | Mirth Action | FHIR Target |
|---|---|---|
| ADT A01 (Admit) | Map PID → Patient, PV1 → Encounter | `POST /fhir/R4` transaction Bundle |
| ADT A03 (Discharge) | Map PV1 → Encounter.status=finished | `POST /fhir/R4/Encounter` |
| ADT A08 (Update) | Map PID/PV1 changes | `POST /fhir/R4/Patient` + Encounter upsert |
| ORU R01 (Lab result) | Map OBX → Observation (LOINC in OBX-3) | `POST /fhir/R4/Observation` |

Mirth HTTP Sender destination: `{vigilcare_url}/fhir/R4` with header `X-Api-Key` and content type `application/fhir+json`.