Message type

Pharmacy / treatment give acknowledgment

Acknowledges a pharmacy or treatment order action. The MSA segment reports the acceptance or rejection status. Pharmacy and ordering systems exchange this to confirm processing.

20segments

8required

3groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RRG^O16^RRG_O16|MSG001|P|2.9\r' \
      'ORC|NW|ORD001||GRP001|||1^BID\r' \
      'RXG|1|1|54321^Metformin^NDC|500|mg'

# .. 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
drug = msg.rxg.give_code
dose = msg.rxg.give_amount_minimum

Python examples

Build and parse RRG^O16 messages in Python

How to construct, send, receive, and extract fields from real-world RRG^O16 messages.

Parse an incoming RRG^O16 message

Demonstrates receiving and extracting key fields from a pharmacy / treatment give acknowledgment transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RRG^O16^RRG_O16|MSG001|P|2.9\r' \
      'ORC|NW|ORD001||GRP001|||1^BID\r' \
      'RXG|1|1|54321^Metformin^NDC|500|mg'

# .. 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
drug = msg.rxg.give_code
dose = msg.rxg.give_amount_minimum

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||RRG^O16^RRG_O16|MSG00001|P|2.9\rMSA|AA|MSG00001\rERR|||0|I|'
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: MSA, PID, ORC, TQ1, RXG, TQ1, RXR. 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

RRG^O16 segment composition

Segments that make up the RRG^O16 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	`MSA`	Required	No	Message acknowledgment	-
4	`ERR`	Optional	Yes	Error	-
5	`SFT`	Optional	Yes	Software segment	-
6	`UAC`	Optional	No	User authentication credential	-
7	`NTE`	Optional	Yes	Notes and comments	-
8	`PID`	Required	No	Patient identification	RESPONSE
9	`PRT`	Optional	Yes	Participation information	RESPONSE
10	`NTE`	Optional	Yes	Notes and comments	RESPONSE
11	`ORC`	Required	No	Common order	RESPONSE
12	`PRT`	Optional	Yes	Participation information	RESPONSE
13	`TQ1`	Required	No	Timing / quantity	TIMING
14	`TQ2`	Optional	Yes	Timing / quantity relationship	TIMING
15	`RXG`	Required	No	Pharmacy / treatment give	GIVE
16	`PRT`	Optional	Yes	Participation information	GIVE
17	`TQ1`	Required	No	Timing / quantity	GIVE
18	`TQ2`	Optional	Yes	Timing / quantity relationship	GIVE
19	`RXR`	Required	Yes	Pharmacy / treatment route	GIVE
20	`RXC`	Optional	Yes	Pharmacy / treatment component order	GIVE

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Open source In Python