Track 1 — FHIR Fundamentals

Encounter

An Encounter is a patient interaction with a healthcare provider. A GP visit, an emergency room admission, a video consultation, a home visit — each is an Encounter. It is the context in which clinical decisions are made and clinical data is recorded.

Why Encounter matters

Most clinical resources — Conditions, Observations, MedicationRequests, DiagnosticReports — are recorded in the context of an Encounter. The Encounter binds them together: these results were produced during this visit, by this practitioner, at this location.

Without Encounter, clinical data floats disconnected. With it, you can reconstruct what happened during any given visit: why the patient came in, what was found, what was prescribed, when they left.

Example: Ambulatory check-up (JSON)

{
  "resourceType": "Encounter",
  "id": "encounter-checkup-001",
  "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/patient-001" },
  "participant": [{
    "type": [{
      "coding": [{
        "system": "http://terminology.hl7.org/CodeSystem/v3-ParticipationType",
        "code": "ATND"
      }]
    }],
    "individual": { "reference": "Practitioner/dr-novak-001" }
  }],
  "period": {
    "start": "2026-06-06T09:00:00Z",
    "end": "2026-06-06T09:30:00Z"
  },
  "reasonCode": [{
    "coding": [{
      "system": "http://snomed.info/sct",
      "code": "44054006",
      "display": "Diabetes mellitus type 2"
    }]
  }]
}

Status lifecycle

An Encounter moves through a lifecycle from planning to completion. The status field reflects where in that lifecycle the encounter currently sits.

Status	Meaning
planned	Scheduled but not started
arrived	Patient arrived, encounter not yet started clinically
triaged	Patient assessed (used in emergency settings)
in-progress	Currently happening
onleave	Temporarily absent (e.g. patient left for tests)
finished	Completed — the normal end state
cancelled	Did not happen
entered-in-error	Recorded by mistake

class — type of care setting

class is a required field that describes the broad setting of the encounter. It is coded from the HL7 v3 ActCode system.

Code	Setting
AMB	Ambulatory — outpatient visit, GP consultation, clinic
EMER	Emergency — unplanned, urgent care
IMP	Inpatient — hospital admission
SS	Short Stay — day surgery, observation unit
HH	Home Health — care delivered at patient's home
VR	Virtual — telemedicine, video consultation

Key elements reference

subjectReference to the Patient. Required.

participantWho was present: attending practitioner (ATND), consultant (CON), admitter (ADM). Array — multiple participants per encounter.

periodStart and end date-time of the encounter. Used to filter by date in search queries.

reasonCodeWhy the patient came in — coded with SNOMED CT. Can also use reasonReference to point to a Condition resource.

diagnosisDiagnoses made during this encounter, ranked by role (chief complaint, comorbidity, billing).

serviceProviderReference to the Organization that managed the encounter.

locationWhere the encounter took place. Array — patient can move between locations during a single encounter.