Message type

Order status update

Communicates an update to the status of one or more orders. The ORC segment carries the updated order status. Order management and tracking systems consume this.

10segments

2required

1group

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'OSU^O51^OSU_O51|MSG001|P|2.9\r' \
      'ORC|NW|ORD001||GRP001|||1^BID'

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

# .. whose fields we can now access.
order_control = msg.orc.order_control
order_number = msg.orc.placer_order_number

Python examples

Build and parse OSU^O51 messages in Python

How to construct, send, receive, and extract fields from real-world OSU^O51 messages.

Parse an incoming OSU^O51 message

Demonstrates receiving and extracting key fields from a order status update transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'OSU^O51^OSU_O51|MSG001|P|2.9\r' \
      'ORC|NW|ORD001||GRP001|||1^BID'

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

# .. whose fields we can now access.
order_control = msg.orc.order_control
order_number = msg.orc.placer_order_number

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||OSU^O51^OSU_O51|MSG00001|P|2.9\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rPRT|1||AT^Attending||1234^CHEN^DAVID^L^^^MD'
msg = HL7Message.parse(raw)

order_control = msg.orc.order_control
order_number = msg.orc.placer_order_number

Beyond the mandatory MSH header, the required segments are: ORC. 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

OSU^O51 segment composition

Segments that make up the OSU^O51 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	`NTE`	Optional	Yes	Notes and comments	-
6	`PID`	Optional	No	Patient identification	-
7	`PRT`	Optional	Yes	Participation information	-
8	`ARV`	Optional	Yes	Access restriction	-
9	`ORC`	Required	No	Common order	ORDER_STATUS
10	`PRT`	Optional	Yes	Participation information	ORDER_STATUS

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Open source In Python