Message type

Schedule request

Requests a scheduling action such as booking, modifying, or cancelling an appointment. The ARQ segment carries the appointment request details and resource segments define the requested resources.

26segments

9required

2groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'SRM^S01^SRM_S01|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'AIS|1||CARDIO^Cardiology consult|20260701'

# .. 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
service = msg.ais.universal_service_identifier
start_time = msg.ais.start_date_time

Python examples

Build and parse SRM^S01 messages in Python

How to construct, send, receive, and extract fields from real-world SRM^S01 messages.

Parse an incoming SRM^S01 message

Demonstrates receiving and extracting key fields from a schedule request transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'SRM^S01^SRM_S01|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'AIS|1||CARDIO^Cardiology consult|20260701'

# .. 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
service = msg.ais.universal_service_identifier
start_time = msg.ais.start_date_time

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||SRM^S01^SRM_S01|MSG00001|P|2.9\rARQ|APPT-3001||||||ROUTINE^Routine^HL70276|||15|MIN|^^^20260415090000^20260415091500\rAPR|'
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: ARQ, PID, OBX, RGS, AIS, AIG, AIL, AIP. 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

SRM^S01 segment composition

Segments that make up the SRM^S01 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	`ARQ`	Required	No	Appointment request	-
4	`APR`	Optional	No	Appointment preferences	-
5	`NTE`	Optional	Yes	Notes and comments	-
6	`PID`	Required	No	Patient identification	PATIENT
7	`PRT`	Optional	Yes	Participation information	PATIENT
8	`PV1`	Optional	No	Patient visit	PATIENT
9	`PV2`	Optional	No	Patient visit - additional info	PATIENT
10	`PRT`	Optional	Yes	Participation information	PATIENT
11	`OBX`	Required	No	Observation result	PATIENT
12	`PRT`	Optional	Yes	Participation information	PATIENT
13	`DG1`	Optional	Yes	Diagnosis	PATIENT
14	`RGS`	Required	No	Resource group	RESOURCES
15	`AIS`	Required	No	Appointment information - service	RESOURCES
16	`APR`	Optional	No	Appointment preferences	RESOURCES
17	`NTE`	Optional	Yes	Notes and comments	RESOURCES
18	`AIG`	Required	No	Appointment information - general resource	RESOURCES
19	`APR`	Optional	No	Appointment preferences	RESOURCES
20	`NTE`	Optional	Yes	Notes and comments	RESOURCES
21	`AIL`	Required	No	Appointment information - location resource	RESOURCES
22	`APR`	Optional	No	Appointment preferences	RESOURCES
23	`NTE`	Optional	Yes	Notes and comments	RESOURCES
24	`AIP`	Required	No	Appointment information - personnel resource	RESOURCES
25	`APR`	Optional	No	Appointment preferences	RESOURCES
26	`NTE`	Optional	Yes	Notes and comments	RESOURCES

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Open source In Python