FHIR Encounter Resource (R4)

Encounter is an interaction between a patient and a provider: an office visit, an inpatient stay, a telehealth call. Element table, search parameters, example JSON and FHIRPath for FHIR R4.

FHIR Encounter Resource (R4) — part of the free FHIR Toolbox library.
Runs entirely in your browser: your FHIR data is never uploaded to a server.

Overview

Encounter is an interaction between a patient and a provider: an office visit, an inpatient stay, a telehealth call. It carries the class, status, participants, period and where the care happened. Many resources (Observation, Procedure, Condition) reference an Encounter to say when and in what context they were recorded. Its shape changed noticeably between R4 and R5.

Elements

Element	Type	Cardinality	Description
Encounter.identifier	Identifier	0..*	Identifier(s) by which this encounter is known
Encounter.status	code	1..1	planned \| arrived \| triaged \| in-progress \| onleave \| finished \| cancelled +
Encounter.statusHistory	BackboneElement	0..*	List of past encounter statuses
Encounter.statusHistory.id	String	0..1	Unique id for inter-element referencing
Encounter.statusHistory.extension	Extension	0..*	Additional content defined by implementations
Encounter.statusHistory.modifierExtension	Extension	0..*	Extensions that cannot be ignored even if unrecognized
Encounter.statusHistory.status	code	1..1	planned \| arrived \| triaged \| in-progress \| onleave \| finished \| cancelled +
Encounter.statusHistory.period	Period	1..1	The time that the episode was in the specified status
Encounter.class	Coding	1..1	Classification of patient encounter
Encounter.classHistory	BackboneElement	0..*	List of past encounter classes
Encounter.classHistory.id	String	0..1	Unique id for inter-element referencing
Encounter.classHistory.extension	Extension	0..*	Additional content defined by implementations
Encounter.classHistory.modifierExtension	Extension	0..*	Extensions that cannot be ignored even if unrecognized
Encounter.classHistory.class	Coding	1..1	inpatient \| outpatient \| ambulatory \| emergency +
Encounter.classHistory.period	Period	1..1	The time that the episode was in the specified class
Encounter.type	CodeableConcept	0..*	Specific type of encounter
Encounter.serviceType	CodeableConcept	0..1	Specific type of service
Encounter.priority	CodeableConcept	0..1	Indicates the urgency of the encounter
Encounter.subject	Reference	0..1	The patient or group present at the encounter
Encounter.episodeOfCare	Reference	0..*	Episode(s) of care that this encounter should be recorded against
Encounter.basedOn	Reference	0..*	The ServiceRequest that initiated this encounter
Encounter.participant	BackboneElement	0..*	List of participants involved in the encounter
Encounter.participant.id	String	0..1	Unique id for inter-element referencing
Encounter.participant.extension	Extension	0..*	Additional content defined by implementations
Encounter.participant.modifierExtension	Extension	0..*	Extensions that cannot be ignored even if unrecognized
Encounter.participant.type	CodeableConcept	0..*	Role of participant in encounter
Encounter.participant.period	Period	0..1	Period of time during the encounter that the participant participated
Encounter.participant.individual	Reference	0..1	Persons involved in the encounter other than the patient
Encounter.appointment	Reference	0..*	The appointment that scheduled this encounter
Encounter.period	Period	0..1	The start and end time of the encounter
Encounter.length	Duration	0..1	Quantity of time the encounter lasted (less time absent)
Encounter.reasonCode	CodeableConcept	0..*	Coded reason the encounter takes place
Encounter.reasonReference	Reference	0..*	Reason the encounter takes place (reference)
Encounter.diagnosis	BackboneElement	0..*	The list of diagnosis relevant to this encounter
Encounter.diagnosis.id	String	0..1	Unique id for inter-element referencing
Encounter.diagnosis.extension	Extension	0..*	Additional content defined by implementations
Encounter.diagnosis.modifierExtension	Extension	0..*	Extensions that cannot be ignored even if unrecognized
Encounter.diagnosis.condition	Reference	1..1	The diagnosis or procedure relevant to the encounter
Encounter.diagnosis.use	CodeableConcept	0..1	Role that this diagnosis has within the encounter (e.g. admission, billing, discharge …)
Encounter.diagnosis.rank	positiveInt	0..1	Ranking of the diagnosis (for each role type)
Encounter.account	Reference	0..*	The set of accounts that may be used for billing for this Encounter
Encounter.hospitalization	BackboneElement	0..1	Details about the admission to a healthcare service
Encounter.hospitalization.id	String	0..1	Unique id for inter-element referencing
Encounter.hospitalization.extension	Extension	0..*	Additional content defined by implementations
Encounter.hospitalization.modifierExtension	Extension	0..*	Extensions that cannot be ignored even if unrecognized
Encounter.hospitalization.preAdmissionIdentifier	Identifier	0..1	Pre-admission identifier
Encounter.hospitalization.origin	Reference	0..1	The location/organization from which the patient came before admission
Encounter.hospitalization.admitSource	CodeableConcept	0..1	From where patient was admitted (physician referral, transfer)
Encounter.hospitalization.reAdmission	CodeableConcept	0..1	The type of hospital re-admission that has occurred (if any). If the value is absent, then this is not identified as a readmission
Encounter.hospitalization.dietPreference	CodeableConcept	0..*	Diet preferences reported by the patient
Encounter.hospitalization.specialCourtesy	CodeableConcept	0..*	Special courtesies (VIP, board member)
Encounter.hospitalization.specialArrangement	CodeableConcept	0..*	Wheelchair, translator, stretcher, etc.
Encounter.hospitalization.destination	Reference	0..1	Location/organization to which the patient is discharged
Encounter.hospitalization.dischargeDisposition	CodeableConcept	0..1	Category or kind of location after discharge
Encounter.location	BackboneElement	0..*	List of locations where the patient has been
Encounter.location.id	String	0..1	Unique id for inter-element referencing
Encounter.location.extension	Extension	0..*	Additional content defined by implementations
Encounter.location.modifierExtension	Extension	0..*	Extensions that cannot be ignored even if unrecognized
Encounter.location.location	Reference	1..1	Location the encounter takes place
Encounter.location.status	code	0..1	planned \| active \| reserved \| completed

Example JSON (R4)

{
  "resourceType": "Encounter",
  "id": "example",
  "status": "finished",
  "class": {
    "system": "http://terminology.hl7.org/CodeSystem/v3-ActCode",
    "code": "AMB",
    "display": "ambulatory"
  },
  "type": [
    {
      "coding": [
        {
          "system": "http://snomed.info/sct",
          "code": "185349003",
          "display": "Encounter for check up"
        }
      ]
    }
  ],
  "subject": {
    "reference": "Patient/example"
  },
  "period": {
    "start": "2024-05-01T09:00:00Z",
    "end": "2024-05-01T09:45:00Z"
  }
}

FHIRPath

Encounter.status — Encounter status
Encounter.subject.reference — Reference to the patient
Encounter.type.coding.display — Human-readable visit type

Common validation errors

Using R4 shapes against R5: class is a single Coding in R4 but an array of CodeableConcept in R5, and period became actualPeriod.
Using an R4 status value against R5. R4 uses finished; R5 renamed it to completed (and added others).
Sending class as a plain string such as "AMB". It needs the coded structure with system and code.
Leaving subject out. Without it the encounter isn't attached to any patient.

FHIR Toolbox is a free, privacy-first collection of HL7 FHIR utilities by Omindra Labs. Every tool performs zero-server processing — your health data never leaves your device.