Message type

Pharmacy / treatment dispense

Reports the dispensing of a pharmacy or treatment order. The ORC carries order control and RXD reports the dispensed medication, quantity, and dispensing details.

42segments

16required

4groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RDS^O13^RDS_O13|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 RDS^O13 messages in Python

How to construct, send, receive, and extract fields from real-world RDS^O13 messages.

Parse an incoming RDS^O13 message

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

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'RDS^O13^RDS_O13|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||RDS^O13^RDS_O13|MSG00001|P|2.9'
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: PID, PD1, PV1, ORC, TQ1, RXO, NTE, 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

RDS^O13 segment composition

Segments that make up the RDS^O13 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`	Required	No	Patient identification	PATIENT
7	`PD1`	Required	No	Patient additional demographic	PATIENT
8	`PRT`	Optional	Yes	Participation information	PATIENT
9	`ARV`	Optional	Yes	Access restriction	PATIENT
10	`NTE`	Optional	Yes	Notes and comments	PATIENT
11	`AL1`	Optional	Yes	Patient allergy information	PATIENT
12	`PV1`	Required	No	Patient visit	PATIENT
13	`PV2`	Optional	No	Patient visit - additional info	PATIENT
14	`PRT`	Optional	Yes	Participation information	PATIENT
15	`ARV`	Optional	Yes	Access restriction	PATIENT
16	`ORC`	Required	No	Common order	ORDER
17	`PRT`	Optional	Yes	Participation information	ORDER
18	`TQ1`	Required	No	Timing / quantity	ORDER
19	`TQ2`	Optional	Yes	Timing / quantity relationship	ORDER
20	`RXO`	Required	No	Pharmacy / treatment order	ORDER
21	`PRT`	Optional	Yes	Participation information	ORDER
22	`NTE`	Required	Yes	Notes and comments	ORDER_DETAIL_SUPPLEMENT
23	`RXR`	Required	Yes	Pharmacy / treatment route	ORDER_DETAIL_SUPPLEMENT
24	`RXC`	Required	No	Pharmacy / treatment component order	ORDER_DETAIL_SUPPLEMENT
25	`NTE`	Optional	Yes	Notes and comments	ORDER_DETAIL_SUPPLEMENT
26	`RXE`	Required	No	Pharmacy / treatment encoded order	ORDER
27	`PRT`	Optional	Yes	Participation information	ORDER
28	`NTE`	Optional	Yes	Notes and comments	ORDER
29	`TQ1`	Required	No	Timing / quantity	TIMING_ENCODED
30	`TQ2`	Optional	Yes	Timing / quantity relationship	TIMING_ENCODED
31	`RXR`	Required	Yes	Pharmacy / treatment route	ORDER
32	`RXC`	Optional	Yes	Pharmacy / treatment component order	ORDER
33	`RXD`	Required	No	Pharmacy / treatment dispense	ORDER
34	`PRT`	Optional	Yes	Participation information	ORDER
35	`NTE`	Optional	Yes	Notes and comments	ORDER
36	`RXR`	Required	Yes	Pharmacy / treatment route	ORDER
37	`RXC`	Optional	Yes	Pharmacy / treatment component order	ORDER
38	`CDO`	Optional	Yes	Clinical study data object	ORDER
39	`OBX`	Required	No	Observation result	ORDER
40	`PRT`	Optional	Yes	Participation information	ORDER
41	`NTE`	Optional	Yes	Notes and comments	ORDER
42	`FT1`	Optional	Yes	Financial transaction	ORDER

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