Message type

Return referral information

Supports referral and authorization workflows between providers and payers. Key segments include MSH, PID, OBR, OBX. Referral management and authorization systems exchange this.

27segments

9required

5groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RRI^I12^RRI_I12|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 RRI^I12 messages in Python

How to construct, send, receive, and extract fields from real-world RRI^I12 messages.

Parse an incoming RRI^I12 message

Demonstrates receiving and extracting key fields from a return referral information transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RRI^I12^RRI_I12|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||RRI^I12^RRI_I12|MSG00001|P|2.9\rMSA|AA|MSG00001\rRF1||ROUTINE^Routine^HL70283||20260401|20260430\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rACC|20260401\rDG1|1||Z00.00^Encounter for general adult medical exam^I10|||F\rDRG|'
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: AUT, PRD, PID, PR1, AUT, OBR, OBX, PV1. 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

RRI^I12 segment composition

Segments that make up the RRI^I12 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	`MSA`	Optional	No	Message acknowledgment	-
6	`RF1`	Optional	No	Referral information	-
7	`AUT`	Required	No	Authorization information	AUTHORIZATION_CONTACT2
8	`CTD`	Optional	No	Contact data	AUTHORIZATION_CONTACT2
9	`PRD`	Required	No	Provider data	PROVIDER_CONTACT
10	`CTD`	Optional	Yes	Contact data	PROVIDER_CONTACT
11	`PID`	Required	No	Patient identification	-
12	`ACC`	Optional	No	Accident	-
13	`DG1`	Optional	Yes	Diagnosis	-
14	`DRG`	Optional	Yes	Diagnosis related group	-
15	`AL1`	Optional	Yes	Patient allergy information	-
16	`PR1`	Required	No	Procedures	PROCEDURE
17	`AUT`	Required	No	Authorization information	PROCEDURE
18	`CTD`	Optional	No	Contact data	PROCEDURE
19	`OBR`	Required	No	Observation request	OBSERVATION
20	`PRT`	Optional	Yes	Participation information	OBSERVATION
21	`NTE`	Optional	Yes	Notes and comments	OBSERVATION
22	`OBX`	Required	No	Observation result	OBSERVATION
23	`PRT`	Optional	Yes	Participation information	OBSERVATION
24	`NTE`	Optional	Yes	Notes and comments	OBSERVATION
25	`PV1`	Required	No	Patient visit	PATIENT_VISIT
26	`PV2`	Optional	No	Patient visit - additional info	PATIENT_VISIT
27	`NTE`	Optional	Yes	Notes and comments	-

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Open source In Python