This skill parses and explains HL7 v2.5 IHE PAM (Patient Administration Management) messages - the standard healthcare interoperability format for patient administration events. The parser identifies message types, extracts segments and fields, validates structure according to IHE PAM 2.10 specifications, and provides human-readable explanations.

When to use this skill:

Parse and explain any HL7 ADT message (raw HL7 text)
Identify HL7 message type and event code (ADT^A01, ADT^A02, etc.)
Extract and label all segments and fields (MSH, EVN, PID, PV1, PV2)
Validate HL7 message structure and required fields
Understand IHE PAM business rules and field mappings
Debug HL7 message issues or data quality problems
Document HL7 message examples with explanations

HL7 v2.5 Message Format

HL7 messages use specific delimiters:

Field delimiter:        |  (pipe)
Component delimiter:    ^  (caret)
Repetition delimiter:   ~  (tilde)
Escape character:       \  (backslash)
Subcomponent delimiter: &  (ampersand)

Basic Structure:

MSH|^~\&|SendingApp|SendingFacility|ReceivingApp|ReceivingFacility|Timestamp||MessageType|MessageControlId|ProcessingId|VersionId
EVN|EventTypeCode|RecordedDateTime|...
PID|SetId||PatientId||PatientName||BirthDate|Sex|...
PV1|SetId|PatientClass|AssignedPatientLocation|...

Segment Terminators: Each segment ends with carriage return (\r) or newline (\n)

IHE PAM Message Types

ADT Messages (Admit, Discharge, Transfer)

ADT^A01 - Admit/Visit Notification

Purpose: Patient admission to inpatient care or registration

Required Segments:

MSH (Message Header)
EVN (Event Type)
PID (Patient Identification)
PV1 (Patient Visit)

Example:

MSH|^~\&|HEXAFLUX|CHU_PARIS|TARGET|DEST|20260122140000||ADT^A01^ADT_A01|MSG001|P|2.5
EVN|A01|20260122140000|||USER001
PID|1||PAT12345^^^CHU_PARIS^PI||DUPONT^JEAN^^M.||19750315|M|||15 RUE DE LA PAIX^^PARIS^^75001^FRA||(33)612345678
PV1|1|I|CHU_PARIS^CARDIO^LIT_001^CHU_PARIS||||PR_MARTIN^MARTIN^SOPHIE|||CARDIO||||||||||VIS20260122001|||||||||||||||||||||||||20260122140000

Explanation:

Event: A01 (Patient Admission)
Patient: DUPONT JEAN (M.), born 15/03/1975
Patient ID: PAT12345
Visit: VIS20260122001
Location: CHU_PARIS, Cardiology, Bed LIT_001
Admission: 22/01/2026 14:00:00
Patient Class: I (Inpatient)
Attending: Dr. MARTIN SOPHIE

ADT^A02 - Transfer a Patient

Purpose: Patient transfer between units, rooms, or services

Required Segments:

MSH, EVN, PID, PV1
PV2 (optional but recommended for prior location)

Example:

MSH|^~\&|HEXAFLUX|CHU_PARIS|TARGET|DEST|20260123090000||ADT^A02^ADT_A02|MSG002|P|2.5
EVN|A02|20260123090000|||USER002
PID|1||PAT12345^^^CHU_PARIS^PI||DUPONT^JEAN^^M.||19750315|M
PV1|1|I|CHU_PARIS^NEURO^LIT_102^CHU_PARIS||||PR_DURAND^DURAND^PAUL|||NEURO||||||||||VIS20260122001
PV2||||||||||||||||||||||CHU_PARIS^CARDIO^LIT_001^CHU_PARIS

Explanation:

Event: A02 (Patient Transfer)
Patient: PAT12345 (DUPONT JEAN)
From: Cardiology, Bed LIT_001 (PV2-1: prior location)
To: Neurology, Bed LIT_102 (PV1-3: assigned location)
Transfer Time: 23/01/2026 09:00:00

ADT^A03 - Discharge a Patient

Purpose: Patient discharge from hospital

Required Segments:

MSH, EVN, PID, PV1

Example:

MSH|^~\&|HEXAFLUX|CHU_PARIS|TARGET|DEST|20260125180000||ADT^A03^ADT_A03|MSG003|P|2.5
EVN|A03|20260125180000|||USER003
PID|1||PAT12345^^^CHU_PARIS^PI||DUPONT^JEAN^^M.||19750315|M
PV1|1|I|CHU_PARIS^CARDIO^LIT_001^CHU_PARIS||||PR_MARTIN^MARTIN^SOPHIE|||CARDIO||||||||||VIS20260122001|||||||||||||||||||||||||||20260125180000|||||HOME

Explanation:

Event: A03 (Patient Discharge)
Patient: PAT12345 (DUPONT JEAN)
Discharge Time: 25/01/2026 18:00:00 (PV1-45)
Discharge Disposition: HOME (PV1-36)
Visit: VIS20260122001

ADT^A04 - Register a Patient

Purpose: Pre-admission or outpatient registration

Required Segments:

MSH, EVN, PID, PV1

ADT^A05 - Pre-admit a Patient

Purpose: Pre-admission notification

ADT^A06 - Change Outpatient to Inpatient

Purpose: Convert outpatient visit to inpatient admission

ADT^A07 - Change Inpatient to Outpatient

Purpose: Convert inpatient admission to outpatient visit

ADT^A08 - Update Patient Information

Purpose: Update patient demographics

Example:

MSH|^~\&|HEXAFLUX|CHU_PARIS|TARGET|DEST|20260122150000||ADT^A08^ADT_A08|MSG004|P|2.5
EVN|A08|20260122150000|||USER001
PID|1||PAT12345^^^CHU_PARIS^PI||DUPONT^JEAN^^M.||19750315|M|||15 RUE DE LA PAIX^^PARIS^^75001^FRA||(33)612345678|||||||1234567890123||FRA
PV1|1|O||||||||||||||||||||VIS20260122001

Explanation:

Event: A08 (Update Patient Information)
Patient: PAT12345 demographics updated
Updated Fields: Address, phone, national identifier (NIR)

ADT^A11 - Cancel Admit

Purpose: Cancel a previous admission

ADT^A12 - Cancel Transfer

Purpose: Cancel a previous transfer

ADT^A13 - Cancel Discharge

Purpose: Cancel a previous discharge

Segment Definitions

MSH - Message Header (Required)

Purpose: Message metadata and routing information

Field Structure:

MSH|^~\&|SendingApp|SendingFacility|ReceivingApp|ReceivingFacility|Timestamp||MessageType^EventCode^MessageStructure|MessageControlId|ProcessingId|VersionId

Key Fields:

MSH-3: Sending Application
MSH-4: Sending Facility
MSH-5: Receiving Application
MSH-6: Receiving Facility
MSH-7: Date/Time of Message (YYYYMMDDHHmmss)
MSH-9: Message Type (ADT^A01^ADT_A01)
MSH-10: Message Control ID (unique identifier)
MSH-11: Processing ID (P=Production, T=Training, D=Debugging)
MSH-12: Version ID (2.5)

EVN - Event Type (Required)

Purpose: Event-specific information

Field Structure:

EVN|EventTypeCode|RecordedDateTime|EventDateTime|EventReasonCode|OperatorId

Key Fields:

EVN-1: Event Type Code (A01, A02, A03, etc.)
EVN-2: Recorded Date/Time (when event was recorded)
EVN-3: Event Occurred Date/Time (when event actually occurred)
EVN-5: Operator ID (user who triggered the event)

PID - Patient Identification (Required)

Purpose: Patient demographic information

Field Structure (30+ fields):

PID|SetId||PatientId^^^AssigningAuthority^IdType~AltId||LastName^FirstName^MiddleName^Suffix^Prefix||BirthDate|Sex|PatientAlias|Race|PatientAddress||PhoneHome|PhoneBusiness|PrimaryLanguage|MaritalStatus|Religion|PatientAccountNumber|SSN|DriverLicense|MotherIdentifier|EthnicGroup|BirthPlace|MultipleBirth|BirthOrder|Citizenship|VeteranStatus|Nationality|DeathDateTime|DeathIndicator

Key Fields:

PID-1: Set ID
PID-3: Patient Identifier List (PatientId^^^Facility^PI)
PID-5: Patient Name (LastName^FirstName^MiddleName^Suffix^Prefix)
PID-7: Date of Birth (YYYYMMDD)
PID-8: Sex (M/F/O/U)
PID-11: Patient Address (Street^^City^^PostalCode^Country)
PID-13: Phone Number - Home
PID-14: Phone Number - Business
PID-22: Ethnic Group
PID-29: Death Date and Time
PID-30: Death Indicator (Y/N)

PV1 - Patient Visit (Required)

Purpose: Visit/encounter information

Field Structure (52 fields):

PV1|SetId|PatientClass|AssignedLocation^Room^Bed^Facility|AdmissionType|PreadmitNumber|PriorLocation|AttendingDoctor^LastName^FirstName|ReferringDoctor|ConsultingDoctor|HospitalService|TemporaryLocation|PreadmitTestIndicator|ReadmissionIndicator|AdmitSource|AmbulatoryStatus|VIPIndicator|AdmittingDoctor|PatientType|VisitNumber|FinancialClass

Key Fields:

PV1-1: Set ID
PV1-2: Patient Class (I=Inpatient, O=Outpatient, E=Emergency, R=Recurring)
PV1-3: Assigned Patient Location (Facility^Service^Room^Bed)
PV1-4: Admission Type (E=Emergency, R=Routine, etc.)
PV1-6: Prior Patient Location (for transfers)
PV1-7: Attending Doctor (DoctorId^LastName^FirstName)
PV1-10: Hospital Service
PV1-19: Visit Number (unique visit identifier)
PV1-36: Discharge Disposition (HOME, SNF, EXP, etc.)
PV1-44: Admit Date/Time
PV1-45: Discharge Date/Time

PV2 - Patient Visit - Additional Info (Optional)

Purpose: Extended visit information

Key Fields:

PV2-1: Prior Pending Location (for transfers)
PV2-3: Admit Reason
PV2-8: Expected Discharge Date
PV2-9: Expected Discharge Disposition
PV2-47: Expected LOA Return Date/Time

IHE PAM Mandatory Fields

Required for All ADT Messages

MSH-3: Sending Application
MSH-4: Sending Facility
MSH-7: Date/Time of Message
MSH-9: Message Type
MSH-10: Message Control ID
MSH-12: Version ID (2.5)
EVN-1: Event Type Code
EVN-2: Recorded Date/Time
PID-3: Patient Identifier
PID-5: Patient Name
PID-7: Date of Birth
PID-8: Sex

Required for Admission/Transfer Messages (A01, A02)

PV1-2: Patient Class
PV1-3: Assigned Patient Location
PV1-19: Visit Number
PV1-44: Admit Date/Time

Required for Discharge Messages (A03)

PV1-36: Discharge Disposition
PV1-45: Discharge Date/Time

Parsing Logic

When asked to parse an HL7 IHE PAM message:

Split by segment terminator: segments = message.split('\r') or split('\n')
Parse MSH segment (always first):

Extract delimiters from MSH-2: ^~\&

Field delimiter: |
Component delimiter: ^
Repetition delimiter: ~
Escape character: \
Subcomponent delimiter: &
Identify message type: Check MSH-9

ADT^A01 = Admission

ADT^A02 = Transfer
ADT^A03 = Discharge
etc.
Parse each segment:

Split by field delimiter |

Parse components with ^
Parse repetitions with ~
Parse subcomponents with &
Extract key fields:

Patient ID (PID-3)

Patient name (PID-5)
Birth date (PID-7)
Visit number (PV1-19)
Location (PV1-3)
Dates (PV1-44, PV1-45)
Validate structure:

Check required segments present

Check required fields populated
Validate date formats (YYYYMMDD, YYYYMMDDHHmmss)
Validate code values (patient class, sex, etc.)
Generate explanation:

Identify message purpose

Explain event type
List key patient information
Describe visit/encounter details
Provide clinical context

Example Output Format

When parsing a message, provide:

### HL7 IHE PAM Message Analysis

**Raw Message**:

[original HL7 message with visible delimiters]

**Message Identification**:
- Message Type: ADT^A01
- Event Code: A01 (Admit/Visit Notification)
- Message Control ID: [MSH-10]
- Timestamp: [formatted MSH-7]
- Version: 2.5

**MSH - Message Header**:
- Sending Application: [MSH-3]
- Sending Facility: [MSH-4]
- Receiving Application: [MSH-5]
- Receiving Facility: [MSH-6]
- Processing ID: [MSH-11] (Production/Test)

**EVN - Event Type**:
- Event Code: [EVN-1]
- Recorded DateTime: [formatted EVN-2]
- Event Occurred: [formatted EVN-3]
- Operator: [EVN-5]

**PID - Patient Identification**:
- Patient ID: [PID-3]
- Patient Name: [formatted PID-5]
- Date of Birth: [formatted PID-7]
- Sex: [PID-8]
- Address: [formatted PID-11]
- Phone: [PID-13]
- [other relevant fields]

**PV1 - Patient Visit**:
- Patient Class: [PV1-2] ([description])
- Assigned Location: [formatted PV1-3]
- Attending Doctor: [formatted PV1-7]
- Hospital Service: [PV1-10]
- Visit Number: [PV1-19]
- Admit DateTime: [formatted PV1-44]
- [other relevant fields based on message type]

**PV2 - Additional Visit Info** (if present):
- Prior Location: [PV2-1]
- [other relevant fields]

**Business Context**:
[Explain what this message represents, the workflow event, and clinical significance]

**IHE PAM Compliance**:
- Required segments: [✓ or ✗ for MSH, EVN, PID, PV1]
- Required fields: [list of mandatory field validation results]
- Field formats: [✓ or ✗ for dates, codes, etc.]

Common ADT Event Codes

| A01 | Admit/Visit Notification | Patient admission to inpatient care

| A02 | Transfer a Patient | Transfer between units/rooms

| A03 | Discharge a Patient | Patient discharge from hospital

| A04 | Register a Patient | Pre-admission or outpatient registration

| A05 | Pre-admit a Patient | Notification of planned admission

| A06 | Change Outpatient to Inpatient | Status change

| A07 | Change Inpatient to Outpatient | Status change

| A08 | Update Patient Information | Demographics update

| A09 | Patient Departing - Tracking | Patient left facility temporarily

| A10 | Patient Arriving - Tracking | Patient returned to facility

| A11 | Cancel Admit | Cancel previous admission

| A12 | Cancel Transfer | Cancel previous transfer

| A13 | Cancel Discharge | Cancel previous discharge

| A21 | Patient Goes on Leave of Absence | Temporary leave

| A22 | Patient Returns from Leave of Absence | Return from leave

| A28 | Add Person Information | Add new person to database

| A31 | Update Person Information | Update person demographics

Patient Class Codes

| I | Inpatient

| O | Outpatient

| E | Emergency

| P | Preadmit

| R | Recurring patient

| B | Obstetrics

| C | Commercial Account

| N | Not Applicable

| U | Unknown

Discharge Disposition Codes

| HOME | Home or self care

| SNF | Skilled nursing facility

| RH | Rehabilitation facility

| EXP | Expired (deceased)

| HOS | Hospice

| AADVICE | Left against medical advice

| OTH | Other

Validation Rules

Message Structure

First segment MUST be MSH
MSH-1 MUST be |
MSH-2 MUST be ^~\& (encoding characters)
Segments MUST be separated by CR or LF
Fields MUST be separated by |

Required Segments by Message Type

A01, A04, A05: MSH, EVN, PID, PV1
A02: MSH, EVN, PID, PV1 (PV2 recommended for prior location)
A03: MSH, EVN, PID, PV1
A08: MSH, EVN, PID (PV1 optional)
A11, A12, A13: MSH, EVN, PID

Date/Time Formats

Date: YYYYMMDD
DateTime: YYYYMMDDHHmmss or YYYYMMDDHHmmss.SSSS
Time: HHmmss

Patient Identifier Format

PID-3: PatientId^^^AssigningAuthority^IdentifierType
Example: PAT12345^^^CHU_PARIS^PI

Name Format

PID-5: LastName^FirstName^MiddleName^Suffix^Prefix^Degree
Example: DUPONT^JEAN^^M.

Location Format

PV1-3: PointOfCare^Room^Bed^Facility^LocationStatus^PersonLocationType^Building
Example: CHU_PARIS^CARDIO^LIT_001^CHU_PARIS

Reference Documentation

IHE PAM Specification:

French: https://github.com/Interop-Sante/ihe.iti.pam.fr
International: https://profiles.ihe.net/ITI/TF/Volume1/ch-14.html

HL7 v2.5 Standard:

Official: http://www.hl7.eu/HL7v2x/v25/std25/ch02.html
Segments: http://www.hl7.eu/HL7v2x/v25/std25/ch03.html
Data Types: http://www.hl7.eu/HL7v2x/v25/std25/ch02a.html

Related Tools:

simple-hl7 (Node.js): https://github.com/Bugs5382/node-hl7-client
HAPI (Java): https://hapifhir.github.io/hapi-hl7v2/

Quick Reference

Delimiters

|  Field delimiter
^  Component delimiter
~  Repetition delimiter
\  Escape character
&  Subcomponent delimiter

Common Fields

MSH-9  : Message Type (ADT^A01^ADT_A01)
MSH-10 : Message Control ID
EVN-1  : Event Type Code (A01, A02, etc.)
EVN-2  : Recorded DateTime
PID-3  : Patient ID
PID-5  : Patient Name
PID-7  : Birth Date
PID-8  : Sex
PV1-2  : Patient Class (I/O/E)
PV1-3  : Assigned Location
PV1-19 : Visit Number
PV1-44 : Admit DateTime
PV1-45 : Discharge DateTime

安装

HL7 v2.5 Message Format

IHE PAM Message Types

ADT Messages (Admit, Discharge, Transfer)

ADT^A01 - Admit/Visit Notification

ADT^A02 - Transfer a Patient

ADT^A03 - Discharge a Patient

ADT^A04 - Register a Patient

ADT^A05 - Pre-admit a Patient

ADT^A06 - Change Outpatient to Inpatient

ADT^A07 - Change Inpatient to Outpatient

ADT^A08 - Update Patient Information

ADT^A11 - Cancel Admit

ADT^A12 - Cancel Transfer

ADT^A13 - Cancel Discharge

Segment Definitions

MSH - Message Header (Required)

EVN - Event Type (Required)

PID - Patient Identification (Required)

PV1 - Patient Visit (Required)

PV2 - Patient Visit - Additional Info (Optional)

IHE PAM Mandatory Fields

Required for All ADT Messages

Required for Admission/Transfer Messages (A01, A02)

Required for Discharge Messages (A03)

Parsing Logic

Example Output Format

Common ADT Event Codes

Patient Class Codes

Discharge Disposition Codes

Validation Rules

Message Structure

Required Segments by Message Type

Date/Time Formats

Patient Identifier Format

Name Format

Location Format

Reference Documentation

Quick Reference

Delimiters

Common Fields