ADT A02 - Transfer Patient

In hospitals, there might be a need to change patient's physical location (transfer a patient). This HL7 event is useful in notifying other hospital systems that patient has changed the location and required services need to be redirected.

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ADT A02 should not be used when patient is going to a temporary location like O/R, XRAY etc.
Let's understand the scenario:
Patient A was allocated a physical location (Room 101 Bed A)
We received an A02 to transfer patient to (Room 102 Bed B)
I will provide basic details of implementing A12 into your system, but please contact source system administrator before implementing your interface.
There could be many fields in HL7 message or in your system which can identify patient's location (This depends on your EMR configuration or system which mangaes your Admission/Discharge/Transfer).
Common fields are PatientClass(PV1.2), AssignedPatientLocation(PV1.3), PriorPatientLocation(PV1.6) etc. and all of these values would be very meaningful for Healthcare Systems.
In real world, a hospital system could receive many HL7 messages for a patient before A02, but to understand A02 scenario we will discuss only important one - A01 (Admission)
I will include only those fields in example which are required to describe the A02 transfer message.
Suppose, we have received an A01 message for a patient with following details
PatientClass (PV1.2) - I (Important & Requred field)
AssignedLocation (PV1.3) - PointOfCare - IR, Room - 101, Bed - A
AccountStatus (PV1.41) - ADM
after processing this A01 message, we have following details in our system:

PV1.2	AssignedPatientLocation PV1.3			PriorPatientLocation PV1.6			PV1.41	PV2.4
PatientClass	PointOfCare	Room	Bed	PointOfCare	Room	Bed	AccountStatus	TransferReason
I	IR	101	A				ADM

Now, we have received a transfer request by A02 message with following details
PatientClass (PV1.2) - I (Important & Requred field)
AssignedLocation (PV1.3) - PointOfCare - IR, Room - 201, Bed - B
PriorLocation (PV1.6) - PointOfCare - IR, Room - 101, Bed - A
AccountStatus (PV1.41) - ADM
TransferReason (PV2.4) - Reason For Transfer
after processing this we have following details in our system:

PV1.2	AssignedPatientLocation PV1.3			PriorPatientLocation PV1.6			PV1.41	PV2.4
PatientClass	PointOfCare	Room	Bed	PointOfCare	Room	Bed	AccountStatus	TransferReason
I	IR	201	B	IR	101	A	ADM	Reason For Transfer

You can see the magic of A02, the patient's physical loation has been restored to his prior location.

Note:

ADT messages always contain current information except MRG segments
Process all the fieds in PID & PV1 & other segments in message as normal A08 upate message unless specified by source system.
It is recommended not to send any updated fields except required ones in A02. A08 should be used to update any other fields.