ADT^A06 — Change an Outpatient to an Inpatient

The outpatient now requires admission: A06 flips the patient class without breaking the visit number.

Purpose

Typical scenario: a patient is seen in clinic, day-case or the emergency room (PV1-2 = O or E) and their condition then requires full hospital admission. A06 keeps the encounter unique: no need to close an outpatient stay and open a separate inpatient one.

All acts, observations and orders tied to the visit number stay attached to the same encounter: billing chain, longitudinal patient record and KPIs remain continuous.

Segment structure

ADT_A06
  MSH                    Message Header (mandatory)
  [ SFT ]                Software Segment (optional)
  EVN                    Event Type (mandatory)
  PID                    Patient Identification (mandatory)
  [ PD1 ]                Patient Additional Demographics (optional)
  [ { ROL } ]            Role (optional, repeatable)
  [ MRG ]                Merge Patient Information (optional)
  [ { NK1 } ]            Next of Kin (optional, repeatable)
  PV1                    Patient Visit (mandatory)
  [ PV2 ]                Patient Visit - Additional Info (optional)
  [ { ROL } ]            Role (optional, repeatable)
  [ { DB1 } ]            Disability (optional, repeatable)
  [ { OBX } ]            Observation (optional, repeatable)
  [ { AL1 } ]            Allergy (optional, repeatable)
  [ { DG1 } ]            Diagnosis (optional, repeatable)
  [ DRG ]                Diagnosis Related Group (optional)
  [ { PR1 [ { ROL } ] } ] Procedure (optional, repeatable)
  [ { GT1 } ]            Guarantor (optional, repeatable)
  [ { IN1 [IN2] [IN3] } ] Insurance (optional, repeatable)
  [ ACC ]                Accident (optional)
  [ UB1 ]                UB82 Data (optional)
  [ UB2 ]                UB92 Data (optional)

MSH — EVN

• MSH-9: ADT^A06^ADT_A06.
• EVN-2: timestamp of the medical decision to admit.

PV1 — Patient Visit (flip)

• PV1-2: new class I (Inpatient).
• PV1-3: new assigned bed (typically an inpatient bed).
• PV1-6: prior location (clinic, day-case, ER).
• PV1-19: visit number — UNCHANGED.
• PV1-44: inpatient admission date/time (new length-of-stay baseline).

Real-world example

Patient Luisa Garcia, ER consult on 15 May 2026, admitted at 11:30 after a diagnosis of unstable angina. Visit number preserved:

MSH|^~\&|HIS|HOSP01|EHR|CLINIC02|20260515113000||ADT^A06^ADT_A06|MSG00007001|P|2.5.1|||AL|NE
EVN|A06|20260515113000|||DRJONES^Jones^Sarah^^^DR.
PID|1||MRN334455^^^HOSP^MR||GARCIA^LUISA^^^MRS.||19651128|F|||25 RAMBLA CATALUNYA^^BARCELONA^^08007^ES||+34931112233|||M||ACCT2026-OBS01
PV1|1|I|MED^310^A^HOSP01|R|||DRBERNARD^Bernard^Philippe^^^DR.|||CAR|||1||||OBS||||||||||||||||||HOSP01|||||20260515113000||||||||OBS^URG^^HOSP01

Acknowledgment (ACK)

MSH|^~\&|EHR|CLINIC02|HIS|HOSP01|20260515113001||ACK^A06^ACK|ACK00007001|P|2.5.1
MSA|AA|MSG00007001

Common errors

• Visit number changed: PV1-19 must stay identical to the initial outpatient A04.
• A01 sent instead: generates a parallel inpatient encounter alongside the outpatient one; breaks record continuity.
• Missing PV1-44: inpatient admission date is required for DRG / PMSI billing.

Related ADT events

See also: ADT^A07 and FHIR Encounter.