Segment

Segment group trailer

Marks the end of a logical segment group within an HL7 v2 message. It carries a set identifier and an optional group name that must match the corresponding SGH (Segment Group Header). Together, the SGH /SGT pair brackets repeating or nested groups of segments, letting parsers determine exactly where each group ends without relying on segment order heuristics.

2fields

1required

v2.9HL7 version

from zato.hl7v2 import SGT

sgt = SGT()
sgt.set_id_sgt = '1'
sgt.segment_group_name = 'ORDER'

Python examples

Build SGT segments in Python

How to construct and work with real-world SGT segments.

Order group end

Closes the named order group opened by the matching SGH

from zato.hl7v2.v2_9 import SGT

sgt = SGT()
sgt.set_id_sgt = '1'
sgt.segment_group_name = 'ORDER'

Observation group end

Closes an observation group after result segments

from zato.hl7v2.v2_9 import SGT

sgt = SGT()
sgt.set_id_sgt = '2'
sgt.segment_group_name = 'OBSERVATION'

Unnamed group end

Closes a segment group using only the sequence number

from zato.hl7v2.v2_9 import SGT

sgt = SGT()
sgt.set_id_sgt = '3'

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.

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Build and send HL7 v2 messages

Construct HL7 v2 messages from scratch using typed segment classes and send them over MLLP.

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FAQ

Frequently asked questions

SGT marks the end of a logical segment group in an HL7 v2 message. It is always paired with an SGH that opens the same group, and the segments between them form the group content.

Yes, the set_id_sgt value must match the set_id_sgh of the corresponding header so parsers can pair them correctly:

from zato.hl7v2.v2_9 import SGH, SGT

sgh = SGH()
sgh.set_id_sgh = '1'
sgh.segment_group_name = 'ORDER'

sgt = SGT()
sgt.set_id_sgt = '1'
sgt.segment_group_name = 'ORDER'

No, it is optional. When present, it should match the name in the corresponding SGH for clarity:

from zato.hl7v2.v2_9 import SGT

sgt = SGT()
sgt.set_id_sgt = '1'
sgt.segment_group_name = 'PATIENT'

Yes. Close inner groups before outer groups, using set identifiers to match each SGT to its SGH. This maintains a proper nesting hierarchy within the message.

Instantiate SGT and set its fields:

from zato.hl7v2.v2_9 import SGT

sgt = SGT()
sgt.set_id_sgt = '1'
sgt.segment_group_name = 'RESULT'

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

SGT field reference

Complete list of fields in the SGT segment, HL7 v2.9.

#	Python name	Datatype	Usage	Repeatable	Table
1	`set_id_sgt`	`SI`	Required	No	-
2	`segment_group_name`	`ST`	Optional	No	-

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