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Message type

Cancel pre-admit

Cancels a previously submitted pre-admission (ADT^A05). The PID and PV1 segments identify the cancelled pre-admit. Scheduling and pre-certification systems use this to release reserved resources.

14segments
5required
1group
v2.9HL7 version
adt-a38.py
# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'ADT^A38^ADT_A38|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'PV1|1|I|MED^201^A'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
patient_class = msg.pv1.patient_class
location = msg.pv1.assigned_patient_location

Build and parse ADT^A38 messages in Python

How to construct, send, receive, and extract fields from real-world ADT^A38 messages.

1

Parse an incoming ADT^A38 message

Demonstrates receiving and extracting key fields from a cancel pre-admit transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'ADT^A38^ADT_A38|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'PV1|1|I|MED^201^A'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
patient_class = msg.pv1.patient_class
location = msg.pv1.assigned_patient_location

Learn by building

Step-by-step guides for working with HL7 v2 in Zato.

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||ADT^A38^ADT_A38|MSG00001|P|2.9\rEVN|A38|20260401120000\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rPD1|||Family Health Clinic^^12345\rPV1|1|I|MED^201^A^^^MAIN||||1234^CHEN^DAVID^L^^^MD|5678^PATEL^NINA^R^^^MD|||MED|||||||VN-90001|||||||||||||||||||||20260401\rPV2|||^Routine checkup\rDB1|1||N\rDG1|1||Z00.00^Encounter for general adult medical exam^I10|||F\rDRG|'
msg = HL7Message.parse(raw)

name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth

Beyond the mandatory MSH header, the required segments are: EVN, PID, PV1, OBX. 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.

ADT^A38 segment composition

Segments that make up the ADT^A38 message, in order. Groups are shown with their child segments.

#SegmentUsageRepeatsDescriptionGroup
1MSHRequiredNoMessage header-
2ARVOptionalYesAccess restriction-
3SFTOptionalYesSoftware segment-
4UACOptionalNoUser authentication credential-
5EVNRequiredNoEvent type-
6PIDRequiredNoPatient identification-
7PD1OptionalNoPatient additional demographic-
8PV1RequiredNoPatient visit-
9PV2OptionalNoPatient visit - additional info-
10DB1OptionalYesDisability-
11OBXRequiredNoObservation resultOBSERVATION
12PRTOptionalYesParticipation informationOBSERVATION
13DG1OptionalYesDiagnosis-
14DRGOptionalNoDiagnosis related group-

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