Knowledge base
Healthcare InteroperabilityJuly 8, 2026

HL7 v2.4 Event Triggers

SSilhouette AdminSilhouette LLC

This table lists each HL7 v2.4 trigger event with its code, display name and status (Active, Deprecated, New or Backward-compatible).

CodeDisplayStatus
A01ADT/ACK - Admit/visit notificationActive
A02ADT/ACK - Transfer a patientActive
A03ADT/ACK - Discharge/end visitActive
A04ADT/ACK - Register a patientActive
A05ADT/ACK - Pre-admit a patientActive
A06ADT/ACK - Change an outpatient to an inpatientActive
A07ADT/ACK - Change an inpatient to an outpatientActive
A08ADT/ACK - Update patient informationActive
A09ADT/ACK - Patient departing - trackingActive
A10ADT/ACK - Patient arriving - trackingActive
A11ADT/ACK - Cancel admit/visit notificationActive
A12ADT/ACK - Cancel transferActive
A13ADT/ACK - Cancel discharge/end visitActive
A14ADT/ACK - Pending admitActive
A15ADT/ACK - Pending transferActive
A16ADT/ACK - Pending dischargeActive
A17ADT/ACK - Swap patientsActive
A18ADT/ACK - Merge patient informationDeprecated
A19QRY/ADR - Patient queryDeprecated
A20ADT/ACK - Bed status updateActive
A21ADT/ACK - Patient goes on a "leave of absence"Active
A22ADT/ACK - Patient returns from a "leave of absence"Active
A23ADT/ACK - Delete a patient recordActive
A24ADT/ACK - Link patient informationActive
A25ADT/ACK - Cancel pending dischargeActive
A26ADT/ACK - Cancel pending transferActive
A27ADT/ACK - Cancel pending admitActive
A28ADT/ACK - Add person informationActive
A29ADT/ACK - Delete person informationActive
A30ADT/ACK - Merge person informationDeprecated
A31ADT/ACK - Update person informationActive
A32ADT/ACK - Cancel patient arriving - trackingActive
A33ADT/ACK - Cancel patient departing - trackingActive
A34ADT/ACK - Merge patient information - patient ID onlyDeprecated
A35ADT/ACK - Merge patient information - account number onlyDeprecated
A36ADT/ACK - Merge patient information - patient ID and account numberDeprecated
A37ADT/ACK - Unlink patient informationActive
A38ADT/ACK - Cancel pre-admitActive
A39ADT/ACK - Merge person - patient IDDeprecated
A40ADT/ACK - Merge patient - patient identifier listActive
A41ADT/ACK - Merge account - patient account numberActive
A42ADT/ACK - Merge visit - visit numberActive
A43ADT/ACK - Move patient information - patient identifier listActive
A44ADT/ACK - Move account information - patient account numberActive
A45ADT/ACK - Move visit information - visit numberActive
A46ADT/ACK - Change patient IDDeprecated
A47ADT/ACK - Change patient identifier listActive
A48ADT/ACK - Change alternate patient IDDeprecated
A49ADT/ACK - Change patient account numberActive
A50ADT/ACK - Change visit numberActive
A51ADT/ACK - Change alternate visit IDActive
A52ADT/ACK - Cancel leave of absence for a patientActive
A53ADT/ACK - Cancel patient returns from a leave of absenceActive
A54ADT/ACK - Change attending doctorActive
A55ADT/ACK - Cancel change attending doctorActive
A60ADT/ACK - Update allergy informationActive
A61ADT/ACK - Change consulting doctorActive
A62ADT/ACK - Cancel change consulting doctorActive
B01PMU/ACK - Add personnel recordActive
B02PMU/ACK - Update personnel recordActive
B03PMU/ACK - Delete personnel recordActive
B04PMU/ACK - Active practicing personActive
B05PMU/ACK - Deactivate practicing personActive
B06PMU/ACK - Terminate practicing personActive
B07PMU/ACK - Grant Certificate/PermissionActive
B08PMU/ACK - Revoke Certificate/PermissionActive
C01CRM - Register a patient on a clinical trialActive
C02CRM - Cancel a patient registration on clinical trial (for clerical mistakes only)Active
C03CRM - Correct/update registration informationActive
C04CRM - Patient has gone off a clinical trialActive
C05CRM - Patient enters phase of clinical trialActive
C06CRM - Cancel patient entering a phase (clerical mistake)Active
C07CRM - Correct/update phase informationActive
C08CRM - Patient has gone off phase of clinical trialActive
C09CSU - Automated time intervals for reporting, like monthlyActive
C10CSU - Patient completes the clinical trialActive
C11CSU - Patient completes a phase of the clinical trialActive
C12CSU - Update/correction of patient order/result informationActive
CNQCancel QueryActive
E01Submit HealthCare Services InvoiceActive
E02Cancel HealthCare Services InvoiceActive
E03HealthCare Services Invoice StatusActive
E04Re-Assess HealthCare Services Invoice RequestActive
E10Edit/Adjudication ResultsActive
E12Request Additional InformationActive
E13Additional Information ResponseActive
E15Payment/Remittance AdviceActive
E20Submit Authorization RequestActive
E21Cancel Authorization RequestActive
E22Authorization Request StatusActive
E24Authorization ResponseActive
E30Submit Health Document related to Authorization RequestActive (reserved for future)
E31Cancel Health Document related to Authorization RequestActive (reserved for future)
I01RQI/RPI - Request for insurance informationActive
I02RQI/RPL - Request/receipt of patient selection display listActive
I03RQI/RPR - Request/receipt of patient selection listActive
I04RQD/RPI - Request for patient demographic dataActive
I05RQC/RCI - Request for patient clinical informationDeprecated
I06RQC/RCL - Request/receipt of clinical data listingDeprecated
I07PIN/ACK - Unsolicited insurance informationActive
I08RQA/RPA - Request for treatment authorization informationActive
I09RQA/RPA - Request for modification to an authorizationActive
I10RQA/RPA - Request for resubmission of an authorizationActive
I11RQA/RPA - Request for cancellation of an authorizationActive
I12REF/RRI - Patient referralActive
I13REF/RRI - Modify patient referralActive
I14REF/RRI - Cancel patient referralActive
I15REF/RRI - Request patient referral statusActive
I16Collaborative Care ReferralActive
I17Modify Collaborative Care ReferralDeprecated
I18Cancel Collaborative Care ReferralDeprecated
I19Collaborative Care Query/Collaborative Care Query UpdateActive
I20Asynchronous Collaborative Care UpdateActive
I21Collaborative Care MessageActive
I22Collaborative Care Fetch / Collaborative Care InformationActive
J01QCN/ACK - Cancel query/acknowledge messageActive
J02QSX/ACK - Cancel subscription/acknowledge messageActive
K11RSP - Segment pattern response in response to QBP^Q11Active
K13RTB - Tabular response in response to QBP^Q13Active
K15RDY - Display response in response to QBP^Q15Active
K21RSP - Get person demographics responseActive
K22RSP - Find candidates responseActive
K23RSP - Get corresponding identifiers responseActive
K24RSP - Allocate identifiers responseActive
K25RSP - Personnel Information by Segment ResponseActive
K31RSP - Dispense History ResponseActive
K32Find Candidates including Visit Information ResponseActive
K33Get Donor Record Candidates Response MessageActive
K34Segment Pattern Response MessageActive
M01MFN/MFK - Master file not otherwise specifiedDeprecated
M02MFN/MFK - Master file - staff practitionerActive
M03MFN/MFK - Master file - test/observationDeprecated
M04MFN/MFK - Master files charge descriptionActive
M05MFN/MFK - Patient location master fileActive
M06MFN/MFK - Clinical study with phases and schedules master fileActive
M07MFN/MFK - Clinical study without phases but with schedules master fileActive
M08MFN/MFK - Test/observation (numeric) master fileActive
M09MFN/MFK - Test/observation (categorical) master fileActive
M10MFN/MFK - Test/observation batteries master fileActive
M11MFN/MFK - Test/calculated observations master fileActive
M12MFN/MFK - Master file notification messageActive
M13MFN/MFK - Master file notification - generalActive
M14MFN/MFK - Master file notification - site definedActive
M15MFN/MFK - Inventory item master file notificationActive
M16MFN/MFK - Master File Notification Inventory Item EnhancedActive
M17DRG Master File MessageActive
M18MFN/MFK - Master file notification - Test/Observation (Payer)Active
N01NMQ/NMR - Application management query messageDeprecated
N02NMD/ACK - Application management data message (unsolicited)Active
O01ORM - Order message (also RDE, RDS, RGV, RAS)Deprecated
O02ORR - Order response (also RRE, RRD, RRG, RRA)Deprecated
O03OMD - Diet orderActive
O04ORD - Diet order acknowledgmentActive
O05OMS - Stock requisition orderActive
O06ORS - Stock requisition acknowledgmentActive
O07OMN - Non-stock requisition orderActive
O08ORN - Non-stock requisition acknowledgmentActive
O09OMP - Pharmacy/treatment orderActive
O10ORP - Pharmacy/treatment order acknowledgmentActive
O11RDE - Pharmacy/treatment encoded orderActive
O12RRE - Pharmacy/treatment encoded order acknowledgmentActive
O13RDS - Pharmacy/treatment dispenseActive
O14RRD - Pharmacy/treatment dispense acknowledgmentActive
O15RGV - Pharmacy/treatment giveActive
O16RRG - Pharmacy/treatment give acknowledgmentActive
O17RAS - Pharmacy/treatment administrationActive
O18RRA - Pharmacy/treatment administration acknowledgmentActive
O19OMG - General clinical orderActive
O20ORG/ORL - General clinical order responseActive
O21OML - Laboratory orderActive
O22ORL - General laboratory order response message to any OMLActive
O23OMI - Imaging orderActive
O24ORI - Imaging order response message to any OMIActive
O25RDE - Pharmacy/treatment refill authorization requestActive
O26RRE - Pharmacy/Treatment Refill Authorization AcknowledgementActive
O27OMB - Blood product orderActive
O28ORB - Blood product order acknowledgmentActive
O29BPS - Blood product dispense statusActive
O30BRP - Blood product dispense status acknowledgmentActive
O31BTS - Blood product transfusion/dispositionActive
O32BRT - Blood product transfusion/disposition acknowledgmentActive
O33OML - Laboratory order for multiple orders related to a single specimenActive
O34ORL - Laboratory order response message to a multiple order related to single specimen OMLActive
O35OML - Laboratory order for multiple orders related to a single container of a specimenActive
O36ORL - Laboratory order response message to a single container of a specimen OMLActive
O37OPL - Population/Location-Based Laboratory Order MessageActive
O38OPR - Population/Location-Based Laboratory Order Acknowledgment MessageActive
O39Specimen shipment centric laboratory orderActive
O40Specimen Shipment Centric Laboratory Order Acknowledgment MessageActive
O41DBC - Create Donor Record MessageActive
O42DBU - Update Donor Record MessageActive
O43General Order Message with Document Payload Acknowledgement MessageActive
O44Donor Registration - Minimal MessageActive
O45Donor Eligibility Observations MessageActive
O46Donor Eligibility MessageActive
O47Donor Request to Collect MessageActive
O48Donation Procedure MessageActive
O49Pharmacy/Treatment Dispense Request MessageActive
O50Pharmacy/Treatment Encoded Order AcknowledgmentActive
O51OSU - Order Status UpdateNew
O52OSU - Order Status Update AcknowledgementNew
O53ORL - General Laboratory Order Acknowledgment Message (Patient Optional)New
O54ORL - Laboratory Order Acknowledgment Message - Multiple Order Per Specimen (Patient Optional)New
O55ORL - Laboratory Order Acknowledgment Message - Multiple Order Per Container of Specimen (Patient Optional)New
O56ORL - Specimen Shipment Centric Laboratory Order Acknowledgment Message (Patient Optional)New
O57OMQ - General Order Message with Document PayloadBackward-compatible
O58ORX - General Order Message with Document Payload Acknowledgement MessageNew
O59OML - Laboratory order for additional work upNew
P01BAR/ACK - Add patient accountsActive
P02BAR/ACK - Purge patient accountsActive
P03DFT/ACK - Post detail financial transactionActive
P04QRY/DSP - Generate bill and A/R statementsDeprecated
P05BAR/ACK - Update accountActive
P06BAR/ACK - End accountActive
P07PEX - Unsolicited initial individual product experience reportActive
P08PEX - Unsolicited update individual product experience reportActive
P09SUR - Summary product experience reportDeprecated
P10BAR/ACK - Transmit Ambulatory Payment Classification (APC)Active
P11DFT/ACK - Post Detail Financial Transactions - NewActive
P12BAR/ACK - Update Diagnosis/ProcedureActive
PC1PPR - PC/ problem addActive
PC2PPR - PC/ problem updateActive
PC3PPR - PC/ problem deleteActive
PC4QRY - PC/ problem queryDeprecated
PC5PRR - PC/ problem responseDeprecated
PC6PGL - PC/ goal addActive
PC7PGL - PC/ goal updateActive
PC8PGL - PC/ goal deleteActive
PC9QRY - PC/ goal queryDeprecated
PCAPPV - PC/ goal responseDeprecated
PCBPPP - PC/ pathway (problem-oriented) addActive
PCCPPP - PC/ pathway (problem-oriented) updateActive
PCDPPP - PC/ pathway (problem-oriented) deleteActive
PCEQRY - PC/ pathway (problem-oriented) queryDeprecated
PCFPTR - PC/ pathway (problem-oriented) query responseDeprecated
PCGPPG - PC/ pathway (goal-oriented) addActive
PCHPPG - PC/ pathway (goal-oriented) updateActive
PCJPPG - PC/ pathway (goal-oriented) deleteActive
PCKQRY - PC/ pathway (goal-oriented) queryDeprecated
PCLPPT - PC/ pathway (goal-oriented) query responseDeprecated
Q01QRY/DSR - Query sent for immediate responseDeprecated
Q02QRY/QCK - Query sent for deferred responseDeprecated
Q03DSR/ACK - Deferred response to a queryDeprecated
Q04EQQ - Embedded query language queryActive (removed in 2.9)
Q05UDM/ACK - Unsolicited display update messageActive
Q06OSQ/OSR - Query for order statusDeprecated
Q07VQQ - Virtual table queryActive (removed in 2.9)
Q08SPQ - Stored procedure requestActive (removed in 2.9)
Q09RQQ - Event replay queryActive (removed in 2.9)
Q11QBP - Query by parameter requesting an RSP segment pattern responseActive
Q13QBP - Query by parameter requesting an RTB tabular responseActive
Q15QBP - Query by parameter requesting an RDY display responseActive
Q16QSB - Create subscriptionActive
Q17QVR - Query for previous eventsActive
Q21QBP - Get person demographicsActive
Q22QBP - Find candidatesActive
Q23QBP - Get corresponding identifiersActive
Q24QBP - Allocate identifiersActive
Q25QBP - Personnel Information by Segment QueryActive
Q26ROR - Pharmacy/treatment order responseDeprecated
Q27RAR - Pharmacy/treatment administration informationDeprecated
Q28RDR - Pharmacy/treatment dispense informationDeprecated
Q29RER - Pharmacy/treatment encoded order informationDeprecated
Q30RGR - Pharmacy/treatment dose informationDeprecated
Q31QBP - Query Dispense historyActive
Q32Find Candidates including Visit InformationActive
Q33QBP - Get Donor Record CandidatesActive
Q34QBP - Get Donor RecordActive
R01ORU/ACK - Unsolicited transmission of an observation messageActive
R02QRY - Query for results of observationDeprecated
R03QRY/DSR - Display-oriented results, query/unsol. update (backward compatibility; replaced by Q05)Active (removed in 2.9)
R04ORF - Response to query; transmission of requested observationDeprecated
R05QRY/DSR - Query for display results (see Q01)Active (removed in 2.9)
R06UDM - Unsolicited update/display results (see Q05)Active (removed in 2.9)
R07EDR - Enhanced Display ResponseActive (removed in 2.9)
R08TBR - Tabular Data ResponseActive (removed in 2.9)
R09ERP - Event Replay ResponseActive (removed in 2.9)
R0RR0R - Pharmacy prescription order query responseDeprecated (removed in 2.9)
R21OUL - Unsolicited laboratory observationDeprecated
R22OUL - Unsolicited Specimen Oriented Observation MessageActive
R23OUL - Unsolicited Specimen Container Oriented Observation MessageActive
R24OUL - Unsolicited Order Oriented Observation MessageActive
R25OPU - Unsolicited Population/Location-Based Laboratory Observation MessageActive
R26OSM - Unsolicited Specimen Shipment Manifest MessageActive
R30ORU - Unsolicited Point-Of-Care Observation Message Without Existing Order - Place An OrderActive
R31ORU - Unsolicited New Point-Of-Care Observation Message - Search For An OrderActive
R32ORU - Unsolicited Pre-Ordered Point-Of-Care ObservationActive
R33ORA - Observation Report AcknowledgementActive
R40ORU - Unsolicited Report AlarmActive
R41Observation Report Alert AcknowledgementActive
R42ORU - Unsolicited Device Event Observation MessageNew
R43ORU - Unsolicited Patient-Device Association Observation MessageNew
RARRAR - Pharmacy administration information query responseActive (removed in 2.9)
RDRRDR - Pharmacy dispense information query responseActive (removed in 2.9)
RERRER - Pharmacy encoded order information query responseActive (removed in 2.9)
RGRRGR - Pharmacy dose information query responseActive (removed in 2.9)
RORROR - Pharmacy prescription order query responseDeprecated
S01SRM/SRR - Request new appointment bookingActive
S02SRM/SRR - Request appointment reschedulingActive
S03SRM/SRR - Request appointment modificationActive
S04SRM/SRR - Request appointment cancellationActive
S05SRM/SRR - Request appointment discontinuationActive
S06SRM/SRR - Request appointment deletionActive
S07SRM/SRR - Request addition of service/resource on appointmentActive
S08SRM/SRR - Request modification of service/resource on appointmentActive
S09SRM/SRR - Request cancellation of service/resource on appointmentActive
S10SRM/SRR - Request discontinuation of service/resource on appointmentActive
S11SRM/SRR - Request deletion of service/resource on appointmentActive
S12SIU/ACK - Notification of new appointment bookingActive
S13SIU/ACK - Notification of appointment reschedulingActive
S14SIU/ACK - Notification of appointment modificationActive
S15SIU/ACK - Notification of appointment cancellationActive
S16SIU/ACK - Notification of appointment discontinuationActive
S17SIU/ACK - Notification of appointment deletionActive
S18SIU/ACK - Notification of addition of service/resource on appointmentActive
S19SIU/ACK - Notification of modification of service/resource on appointmentActive
S20SIU/ACK - Notification of cancellation of service/resource on appointmentActive
S21SIU/ACK - Notification of discontinuation of service/resource on appointmentActive
S22SIU/ACK - Notification of deletion of service/resource on appointmentActive
S23SIU/ACK - Notification of blocked schedule time slot(s)Active
S24SIU/ACK - Notification of opened ("unblocked") schedule time slot(s)Active
S25SQM/SQR - Schedule query message and responseDeprecated
S26SIU/ACK - Notification that patient did not show up for scheduled appointmentActive
S27SIU/ACK - Broadcast Notification of Scheduled AppointmentsActive
S28SLR/SLS - Request new sterilization lotActive
S29SLR/SLS - Request sterilization lot deletionActive
S30STI/STS - Request itemActive
S31SDR/SDS - Request anti-microbial device dataActive
S32SMD/SMS - Request anti-microbial device cycle dataActive
S33STC/ACK - Notification of sterilization configurationActive
S34SLN/ACK - Notification of sterilization lotActive
S35SLN/ACK - Notification of sterilization lot deletionActive
S36SDN/ACK - Notification of anti-microbial device dataActive
S37SCN/ACK - Notification of anti-microbial device cycle dataActive
S38Containers Prepared for Specimen CollectionNew
S39Specimen Collection SuccessfulNew
S40Specimen Collection UnsuccessfulNew
S41Specimen DepartedNew
S42Specimen ArrivedNew
S43Specimen AcceptedNew
S44Specimen RejectedNew
S45Specimen Re-identifiedNew
S46Specimen De-identifiedNew
S47Specimen Sent to ArchiveNew
S48Specimen Retrieved from ArchiveNew
S49Specimen Disposed ofNew
S50Specimen Procedure Step Successful, with Derived Specimen(s)New
S51Specimen Procedure Step Successful, no Derived Specimen(s)New
S52Specimen Procedure Step UnsuccessfulNew
T01MDM/ACK - Original document notificationActive
T02MDM/ACK - Original document notification and contentActive
T03MDM/ACK - Document status change notificationActive
T04MDM/ACK - Document status change notification and contentActive
T05MDM/ACK - Document addendum notificationActive
T06MDM/ACK - Document addendum notification and contentActive
T07MDM/ACK - Document edit notificationActive
T08MDM/ACK - Document edit notification and contentActive
T09MDM/ACK - Document replacement notificationActive
T10MDM/ACK - Document replacement notification and contentActive
T11MDM/ACK - Document cancel notificationActive
T12QRY/DOC - Document queryDeprecated
U01ESU/ACK - Automated equipment status updateActive
U02ESR/ACK - Automated equipment status requestActive
U03SSU/ACK - Specimen status updateActive
U04SSR/ACK - Specimen status requestActive
U05INU/ACK - Automated equipment inventory updateActive
U06INR/ACK - Automated equipment inventory requestActive
U07EAC/ACK - Automated equipment commandActive
U08EAR/ACK - Automated equipment responseActive
U09EAN/ACK - Automated equipment notificationActive
U10TCU/ACK - Automated equipment test code settings updateActive
U11TCR/ACK - Automated equipment test code settings requestActive
U12LSU/ACK - Automated equipment log/service updateActive
U13LSR/ACK - Automated equipment log/service requestActive
U14INR/ACK - Automated Equipment Inventory RequestActive
V01VXQ - Query for vaccination recordDeprecated
V02VXX - Response to vaccination query returning multiple PID matchesDeprecated
V03VXR - Vaccination record responseDeprecated
V04VXU - Unsolicited vaccination record updateActive
W01ORU - Waveform result, unsolicited transmission of requested informationDeprecated
W02QRF - Waveform result, response to queryDeprecated
X01PEX - Product experienceActive (removed in 2.9)
variesMFQ/MFR - Master files query (use event same as asking for e.g., M05 - location)Deprecated

Free Resources

  • HL7 Version 2.x Standard - The official HL7 v2 specification covering message structure, segment definitions and trigger events. Free for personal use with HL7 membership.
  • HAPI HL7v2 Library - An open-source Java library for parsing and generating HL7 v2 messages; includes examples and tutorials for working with segments and trigger codes.
  • NextGen Connect (Mirth) - A free, open-source HL7 interface engine that routes, transforms and monitors HL7 messages, making it easier to test segments and triggers.
  • HL7 Inspector - A lightweight, open-source tool for viewing, validating and debugging HL7 v2 messages.
  • HL7 V2+ Management Group - HL7's central resource hub for v2 messaging, offering consolidated guidance, implementation notes and tooling recommendations.

Need help adopting HL7? From v2 messaging to CDA and FHIR, our experts can streamline integration and ensure compliance. Get in touch to make your healthcare systems work seamlessly together.

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