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Healthcare/HL7 v2/OM5
Segment

Observation batteries (sets)

Defines an observation battery (panel or profile) as a set of component observations, carrying the list of observation identifiers included in the battery. It follows OM1 for panel-type observations (such as a Basic Metabolic Panel or CBC) in MFN messages, enabling ordering systems to expand a single panel order into its constituent test components.

3fields
0required
v2.9HL7 version
om5.py
from zato.hl7v2.v2_9 import OM5
from zato.hl7v2.v2_9 import CWE

om5 = OM5()
om5.sequence_number_test_observation_master_file = '1'
om5.test_observations_included_within_an_ordered_test_battery = CWE(
    identifier='2345-7',
    text='Glucose fasting',
    name_of_coding_system='LN'
)
om5.observation_id_suffixes = 'CMP'
Python examples

Build OM5 segments in Python

How to construct and work with real-world OM5 segments.

1

Comprehensive metabolic battery

Master-file row listing chemistry tests bundled under one battery code

from zato.hl7v2.v2_9 import OM5
from zato.hl7v2.v2_9 import CWE

om5 = OM5()
om5.sequence_number_test_observation_master_file = '1'
om5.test_observations_included_within_an_ordered_test_battery = [
    CWE(
        identifier='2345-7',
        text='Glucose fasting',
        name_of_coding_system='LN',
    ),
    CWE(
        identifier='2951-2',
        text='Sodium',
        name_of_coding_system='LN',
    ),
    CWE(
        identifier='2160-0',
        text='Creatinine',
        name_of_coding_system='LN',
    ),
]
om5.observation_id_suffixes = 'CMP'
2

Lipid wellness panel

Battery tying total cholesterol, HDL, and triglycerides for screening

from zato.hl7v2.v2_9 import OM5
from zato.hl7v2.v2_9 import CWE

om5 = OM5()
om5.sequence_number_test_observation_master_file = '2'
om5.test_observations_included_within_an_ordered_test_battery = [
    CWE(
        identifier='2093-3',
        text='Cholesterol total',
        name_of_coding_system='LN',
    ),
    CWE(
        identifier='2085-9',
        text='HDL cholesterol',
        name_of_coding_system='LN',
    ),
    CWE(
        identifier='2571-8',
        text='Triglycerides',
        name_of_coding_system='LN',
    ),
]
om5.observation_id_suffixes = 'LIPID'
3

Vitamin screening bundle

Repeat field lists vitamin markers included in one catalog battery

from zato.hl7v2.v2_9 import OM5
from zato.hl7v2.v2_9 import CWE

om5 = OM5()
om5.sequence_number_test_observation_master_file = '3'
om5.test_observations_included_within_an_ordered_test_battery = [
    CWE(
        identifier='33747-0',
        text='Vitamin D 25-OH',
        name_of_coding_system='LN',
    ),
    CWE(
        identifier='2132-9',
        text='Vitamin B12',
        name_of_coding_system='LN',
    ),
]
om5.observation_id_suffixes = 'VIT'
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
Related segments

Commonly used with OM5

MFI Master file identification MFE Master file entry OM1 General segment OM2 Observation text OM3 Observation specimen OBR Observation request
FAQ

Frequently asked questions

OM1 describes each observation generically, while OM5 defines which observations fire together as a named battery so wellness panels stay consistent when a single order code is chosen.

Each repetition is one CWE observation that belongs to the battery. Receivers expand HL70662-coded entries into the ordered list used for scheduling and reporting.

Build a list of CWE values and bind it to the repeatable field:

from zato.hl7v2.v2_9 import OM5
from zato.hl7v2.v2_9 import CWE

om5 = OM5()
om5.sequence_number_test_observation_master_file = '1'
om5.test_observations_included_within_an_ordered_test_battery = CWE(
    identifier='2345-7',
    text='Glucose fasting',
    name_of_coding_system='LN'
)

Field 3 carries short suffix tokens that disambiguate catalog keys when the same LOINC mix appears under multiple wellness program names.

OBR placer or filler service codes can reference the battery defined in OM5 so one order line expands to the OBX result set expected for screening programs.

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

OM5 field reference

Complete list of fields in the OM5 segment, HL7 v2.9.

#Python nameDatatypeUsageRepeatableTable
1sequence_number_test_observation_master_fileNMOptionalNo-
2▶test_observations_included_within_an_ordered_test_batteryCWEOptionalYesHL70662
3observation_id_suffixesSTOptionalNo-

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