Message type

Swap patients

Swaps the locations of two patients. Two PID/PV1 pairs identify each patient and their new assignments. Bed boards and census systems consume this to update both room records in a single transaction.

19segments

8required

2groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'ADT^A17^ADT_A17|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'PV1|1|I|MED^201^A'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
patient_class = msg.pv1.patient_class
location = msg.pv1.assigned_patient_location

Python examples

Build and parse ADT^A17 messages in Python

How to construct, send, receive, and extract fields from real-world ADT^A17 messages.

Parse an incoming ADT^A17 message

Demonstrates receiving and extracting key fields from a swap patients transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'ADT^A17^ADT_A17|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'PV1|1|I|MED^201^A'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
patient_class = msg.pv1.patient_class
location = msg.pv1.assigned_patient_location

Tutorials

Learn by building

Step-by-step guides for working with HL7 v2 in Zato.

MLLP

Receive and parse HL7 v2 messages

Set up an MLLP channel, parse incoming messages, and respond with acknowledgments.

Start tutorial Build

Build and send HL7 v2 messages

Construct HL7 v2 messages from scratch using typed segment classes and send them over MLLP.

Start tutorial

FAQ

Frequently asked questions

Use the HL7v2 message parser to extract the typed structure. The parsed message gives you direct access to every segment and field by name.

from zato.hl7v2 import HL7Message

raw = 'MSH|^~\&|SENDER|FACILITY|RECEIVER|DEST|20260401120000||ADT^A17^ADT_A17|MSG00001|P|2.9\rEVN|A17|20260401120000\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rPD1|||Family Health Clinic^^12345\rPV1|1|I|MED^201^A^^^MAIN||||1234^CHEN^DAVID^L^^^MD|5678^PATEL^NINA^R^^^MD|||MED|||||||VN-90001|||||||||||||||||||||20260401\rPV2|||^Routine checkup\rDB1|1||N\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rPV1|1|I|MED^201^A^^^MAIN||||1234^CHEN^DAVID^L^^^MD|5678^PATEL^NINA^R^^^MD|||MED|||||||VN-90001|||||||||||||||||||||20260401'
msg = HL7Message.parse(raw)

name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth

Beyond the mandatory MSH header, the required segments are: EVN, PID, PV1, OBX, PID, PV1, OBX. Optional segments provide additional detail when available.

Zato connects to any system that speaks HL7v2 over MLLP or FHIR over REST. This includes Epic, Cerner, Meditech, Allscripts, and other EHR platforms.

Yes, Zato has built-in MLLP support for sending and receiving HL7v2 messages. MLLP channels handle the framing protocol automatically.

Zato supports HL7 v2.9, which is backward compatible with earlier versions including v2.3, v2.5, and v2.7. Standard segments and datatypes are available as typed Python classes.

Yes. Zato handles both HL7v2 and FHIR natively, so you can parse v2 messages and build FHIR resources with IG-specific extensions in the same service. Typed Python classes are available for both protocols, including extensions from US Core, UK Core, Da Vinci, and other Implementation Guides.

Reference

ADT^A17 segment composition

Segments that make up the ADT^A17 message, in order. Groups are shown with their child segments.

#	Segment	Usage	Repeats	Description	Group
1	`MSH`	Required	No	Message header	-
2	`ARV`	Optional	Yes	Access restriction	-
3	`SFT`	Optional	Yes	Software segment	-
4	`UAC`	Optional	No	User authentication credential	-
5	`EVN`	Required	No	Event type	-
6	`PID`	Required	No	Patient identification	-
7	`PD1`	Optional	No	Patient additional demographic	-
8	`PV1`	Required	No	Patient visit	-
9	`PV2`	Optional	No	Patient visit - additional info	-
10	`DB1`	Optional	Yes	Disability	-
11	`OBX`	Required	No	Observation result	OBSERVATION_RESULT_1
12	`PRT`	Optional	Yes	Participation information	OBSERVATION_RESULT_1
13	`PID`	Required	No	Patient identification	-
14	`PD1`	Optional	No	Patient additional demographic	-
15	`PV1`	Required	No	Patient visit	-
16	`PV2`	Optional	No	Patient visit - additional info	-
17	`DB1`	Optional	Yes	Disability	-
18	`OBX`	Required	No	Observation result	OBSERVATION_RESULT_2
19	`PRT`	Optional	Yes	Participation information	OBSERVATION_RESULT_2

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Open source In Python