HL7 ADT_A02 Transfer a Patient

The bed, ward, unit, or service changed, but the visit continues.
HL7 message structure ADT_A02 groups and segments from HL7 v2.5.1 Hide structure

These are the generated groups and segments for the version selected at the top of the page. The article explains the workflow, and this panel follows the chosen HL7 version.

Message Structure

SegmentNameRequiredRepeatable
MSH
 Message Header Yes No
SFT
 Software Segment No Yes
EVN
 Event Type Yes No
PID
 Patient Identification Yes No
PD1
 Patient Additional Demographic No No
ROL
 Role No Yes
PV1
 Patient Visit Yes No
PV2
 Patient Visit - Additional Information No No
ROL
 Role No Yes
DB1
 Disability No Yes
OBX
 Observation/Result No Yes
PDA
 Patient Death and Autopsy No No

ADT_A02 is the transfer message. It says the patient is still in the same overall encounter, but the visit state has moved: a new ward, room, bed, nursing unit, service, or responsible location. Bed boards, pharmacy dispensing, meal systems, clinical worklists, and ancillary systems all care about this because they use location to decide who can see, serve, route, or charge for the patient.

The clean mental model is this: A01 starts the stay, A02 moves the patient inside that stay, and A03 ends it. If your feed blurs those lines, downstream systems start inventing their own rules, and those rules are rarely the same.

A small A02 example

MSH|^~\&|ADT|CITYHOSP|PHARM|CITYHOSP|20260715141500||ADT^A02^ADT_A02|ADT00002|P|2.5.1 EVN|A02|20260715141200 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F PV1|1|I|WARD2^205^1^CITYHOSP^^BED||WARD1^101^1^CITYHOSP^^BED|||12345^Careful^Clara|||||||||||VN000345^^^CITYHOSP^VN

What systems do with it

The sending PAS or EHR usually broadcasts A02 after a transfer is confirmed. Receivers update current location, service, attending team, census, medication delivery destination, and location-based rules. Some systems also keep a movement history, so the event time in EVN and the location details in PV1 matter.

For most interfaces, PID identifies the patient and PV1 carries both the current and prior location. Receivers often use PV1-3 as the new assigned location and PV1-6 as the prior location, but exact usage is one of those things that should be written down in the interface spec, not discovered during a bed-board incident.

Location and visit identifiers

Keep the visit number stable. A transfer should normally reuse the same PV1-19 visit number from the admission. If the visit number changes, the receiver may interpret the event as a new encounter instead of a movement.

Location components are also worth preserving. Ward, room, bed, facility, and location status should not be flattened into a single display string if the receiver needs to route orders, medication delivery, or census counts by unit.

Implementation traps

Do not use A02 for a pending transfer unless the receiver expects that local convention. HL7 has pending and cancel-pending transfer events in some versions and profiles. Also be careful with late or corrected transfer messages; receivers need a clear rule for whether a late event rewrites the current location or is stored only as history.

Reference notes

The HL7 patient administration chapter describes transfer events as part of ADT workflows, and the local generated HL7 v2.5.1 structure above shows the compact A02 shape: MSH, EVN, PID, PV1, and optional supporting detail.