HL7 for emergency department workflows

ED feeds are fast-moving ADT plus clinical fragments, and timing matters.

Emergency department HL7 is usually a bundle of ADT movement, registration, triage, orders, results, documents, and sometimes public-health reporting. The message that starts the visit is often ADT_A04, with later ADT_A08 updates, ADT_A03 discharge/end-visit events, and orders/results flowing around them.

The receiver needs to treat ED patient class, location, arrival time, provider, chief complaint, diagnosis, and discharge disposition as changing facts. A clean parse is not enough if the feed processes an update after discharge in the wrong order.

MSH|^~\&|ED|CITYHOSP|EHR|CITYHOSP|20260715154000||ADT^A04^ADT_A01|ED000501|P|2.5.1 EVN|A04|20260715153800 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F PV1|1|E|ED^TRIAGE^3^CITYHOSP||||12345^Careful^Clara^^^^^^NPI||||EMR|||||||12345^Careful^Clara^^^^^^NPI|EMER|VNED7788^^^CITYHOSP^VN DG1|1||R07.9^Chest pain, unspecified^I10|||A OBX|1|CE|8661-1^Chief complaint^LN||R07.9^Chest pain^I10||||||F OBX|2|NM|9279-1^Respiratory rate^LN||22|/min|12-20|H|||F

This is synthetic sample data for learning and testing. Open it in HL7 Soup Web before mapping it so the segment groups, repeated fields, and coded values are visible.

Timing And State Are The Hard Part

ED workflows move quickly. A patient may register, triage, move rooms, receive orders, get results, change provider, and discharge within a short window. If your interface is file-based or asynchronous, design for out-of-order arrival and duplicate resends.

IHE ITI Patient Encounter Management is a useful model because it treats encounter creation, update, cancellation, and movements as explicit encounter events rather than vague patient updates.

  • Keep PV1-2 patient class and PV1-3 location structured.
  • Preserve visit number and account identifiers.
  • Treat cancellation and discharge events as first-class workflow events.

ED Data Often Feeds Public Health

Syndromic surveillance feeds commonly draw from ED, urgent care, ambulatory, and inpatient data. CDC's NSSP implementation-guide page lists current and previous syndromic surveillance guides and explicitly ties them to HL7 2.5.1. That means an ED interface may have both a clinical receiver and a public-health receiver with different validation rules.

A Practical Integration Soup Workflow

In Integration Soup, route ED ADT, orders, results, and public-health extracts separately. Log message time, event time, visit number, patient class, location, and trigger event. Use filters for A04/A08/A03 behavior rather than pushing every event through one generic update path.

The Test Pack I Would Ask For

Ask for registration, triage update, location move, order, result, diagnosis update, discharge, cancel registration, duplicate resend, and a syndromic-surveillance extract if public-health reporting is in scope.