Message type

Patient referral

Submits a patient referral from one provider to another. The PID segment identifies the patient, RF1 carries referral details, and provider segments identify the referring and receiving providers.

31segments

10required

6groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

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

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

Parse an incoming REF^I12 message

Demonstrates receiving and extracting key fields from a patient referral transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'REF^I12^REF_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||REF^I12^REF_I12|MSG00001|P|2.9\rRF1||ROUTINE^Routine^HL70283||20260401|20260430\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rNK1|1|JOHNSON^MICHAEL|SPO^Spouse|100 Oak Lane^^Portland^OR^97201|5035551234\rGT1|1||JOHNSON^SARAH^M||100 Oak Lane^^Portland^OR^97201|5035559876\rACC|20260401\rDG1|1||Z00.00^Encounter for general adult medical exam^I10|||F'
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, IN1, PR1, AUT, OBR, 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

REF^I12 segment composition

Segments that make up the REF^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	`RF1`	Optional	No	Referral information	-
6	`AUT`	Required	No	Authorization information	AUTHORIZATION_CONTACT2
7	`CTD`	Optional	No	Contact data	AUTHORIZATION_CONTACT2
8	`PRD`	Required	No	Provider data	PROVIDER_CONTACT
9	`CTD`	Optional	Yes	Contact data	PROVIDER_CONTACT
10	`PID`	Required	No	Patient identification	-
11	`NK1`	Optional	Yes	Next of kin / associated parties	-
12	`GT1`	Optional	Yes	Guarantor	-
13	`IN1`	Required	No	Insurance	INSURANCE
14	`IN2`	Optional	No	Insurance additional info	INSURANCE
15	`IN3`	Optional	No	Insurance additional info - certification	INSURANCE
16	`ACC`	Optional	No	Accident	-
17	`DG1`	Optional	Yes	Diagnosis	-
18	`DRG`	Optional	Yes	Diagnosis related group	-
19	`AL1`	Optional	Yes	Patient allergy information	-
20	`PR1`	Required	No	Procedures	PROCEDURE
21	`AUT`	Required	No	Authorization information	PROCEDURE
22	`CTD`	Optional	No	Contact data	PROCEDURE
23	`OBR`	Required	No	Observation request	OBSERVATION
24	`PRT`	Optional	Yes	Participation information	OBSERVATION
25	`NTE`	Optional	Yes	Notes and comments	OBSERVATION
26	`OBX`	Required	No	Observation result	OBSERVATION
27	`PRT`	Optional	Yes	Participation information	OBSERVATION
28	`NTE`	Optional	Yes	Notes and comments	OBSERVATION
29	`PV1`	Required	No	Patient visit	PATIENT_VISIT
30	`PV2`	Optional	No	Patient visit - additional info	PATIENT_VISIT
31	`NTE`	Optional	Yes	Notes and comments	-

Ready to build integrations?

Get started with Zato and connect your systems in minutes.

Get started ▶Read the docs

Open source In Python