Message type

Pharmacy / treatment dispense information

Returns pharmacy dispense information in response to a query. The RXD segments carry dispensing history and RXR segments specify routes. Pharmacy information systems and medication reconciliation tools consume this.

21segments

11required

4groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RDR^RDR^RDR_RDR|MSG001|P|2.9\r' \
      'ORC|NW|ORD001||GRP001|||1^BID\r' \
      'RXD|1|54321^Metformin^NDC|20260701|60|TAB'

# .. 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.rxd.dispense_give_code
quantity = msg.rxd.actual_dispense_amount

Python examples

Build and parse RDR^RDR messages in Python

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

Parse an incoming RDR^RDR message

Demonstrates receiving and extracting key fields from a pharmacy / treatment dispense information transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RDR^RDR^RDR_RDR|MSG001|P|2.9\r' \
      'ORC|NW|ORD001||GRP001|||1^BID\r' \
      'RXD|1|54321^Metformin^NDC|20260701|60|TAB'

# .. 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.rxd.dispense_give_code
quantity = msg.rxd.actual_dispense_amount

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||RDR^RDR^RDR_RDR|MSG00001|P|2.9\rMSA|AA|MSG00001\rERR|||0|I|\rDSC|CONT-001'
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, QRD, PID, ORC, TQ1, RXE, 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

RDR^RDR segment composition

Segments that make up the RDR^RDR message, in order. Groups are shown with their child segments.

#	Segment	Usage	Repeats	Description	Group
1	`MSH`	Required	No	Message header	-
2	`MSA`	Required	No	Message acknowledgment	-
3	`ERR`	Optional	Yes	Error	-
4	`SFT`	Optional	No	Software segment	-
5	`UAC`	Optional	No	User authentication credential	-
6	`QRD`	Required	No	Original-style query definition	DEFINITION
7	`QRF`	Optional	No	Original-style query filter	DEFINITION
8	`PID`	Required	No	Patient identification	DEFINITION
9	`NTE`	Optional	Yes	Notes and comments	DEFINITION
10	`ORC`	Required	No	Common order	DEFINITION
11	`TQ1`	Required	No	Timing / quantity	TIMING
12	`TQ2`	Optional	Yes	Timing / quantity relationship	TIMING
13	`RXE`	Required	No	Pharmacy / treatment encoded order	ENCODING
14	`TQ1`	Required	No	Timing / quantity	ENCODING
15	`TQ2`	Optional	Yes	Timing / quantity relationship	ENCODING
16	`RXR`	Required	Yes	Pharmacy / treatment route	ENCODING
17	`RXC`	Optional	Yes	Pharmacy / treatment component order	ENCODING
18	`RXD`	Required	No	Pharmacy / treatment dispense	DISPENSE
19	`RXR`	Required	Yes	Pharmacy / treatment route	DISPENSE
20	`RXC`	Optional	Yes	Pharmacy / treatment component order	DISPENSE
21	`DSC`	Optional	No	Continuation pointer	-

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