Message type

Request additional information

Supports health care services invoicing workflows. Key segments include MSH, OBR. Payer and provider systems exchange this for claims processing, authorization, and payment reconciliation.

18segments

6required

1group

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'EHC^E12^EHC_E12|MSG001|P|2.9\r' \
      'IVC|INV001|20260701|1500.00|USD\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M'

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

# .. whose fields we can now access.
invoice_number = msg.ivc.provider_invoice_number
invoice_amount = msg.ivc.invoice_amount
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth

Python examples

Build and parse EHC^E12 messages in Python

How to construct, send, receive, and extract fields from real-world EHC^E12 messages.

Parse an incoming EHC^E12 message

Demonstrates receiving and extracting key fields from a request additional information transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'EHC^E12^EHC_E12|MSG001|P|2.9\r' \
      'IVC|INV001|20260701|1500.00|USD\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M'

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

# .. whose fields we can now access.
invoice_number = msg.ivc.provider_invoice_number
invoice_amount = msg.ivc.invoice_amount
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth

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||EHC^E12^EHC_E12|MSG00001|P|2.9\rRFI|20260401|20260430\rCTD|PRD^Provider\rIVC|INV-001|INV-001\rPSS|1|PSS-001\rPSG|1|PSG-001\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rPRT|1||AT^Attending||1234^CHEN^DAVID^L^^^MD\rPSL|1|PSL-001'
msg = HL7Message.parse(raw)

invoice_number = msg.ivc.provider_invoice_number
invoice_amount = msg.ivc.invoice_amount

Beyond the mandatory MSH header, the required segments are: RFI, IVC, PSS, PSG, OBR. 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

EHC^E12 segment composition

Segments that make up the EHC^E12 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	Yes	User authentication credential	-
5	`RFI`	Required	No	Request for information	-
6	`CTD`	Optional	Yes	Contact data	-
7	`IVC`	Required	No	Invoice segment	-
8	`PSS`	Required	No	Product / service section	-
9	`PSG`	Required	No	Product / service group	-
10	`PID`	Optional	No	Patient identification	-
11	`PRT`	Optional	Yes	Participation information	-
12	`PSL`	Optional	Yes	Product / service line item	-
13	`CTD`	Optional	No	Contact data	REQUEST
14	`OBR`	Required	No	Observation request	REQUEST
15	`PRT`	Optional	Yes	Participation information	REQUEST
16	`NTE`	Optional	No	Notes and comments	REQUEST
17	`OBX`	Optional	Yes	Observation result	REQUEST
18	`PRT`	Optional	Yes	Participation information	REQUEST

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