Reference (Encounter); Observation: CodeableConcept vs Coding

Di lesson 0004 Anda membedakan id dan identifier. Sekarang kita lihat bagaimana resource memakai keduanya untuk saling merujuk (lewat Encounter), lalu membaca nilai berkode di Observation.

Semua JSON di lesson ini diadaptasi (dipendekkan) dari contoh resmi spesifikasi FHIR R4 (4.0.1); tautannya ada di setiap blok. Tanpa lab: cukup baca, jawab kuis, lalu latihan lisan. Kuis di sini adalah feedback cepat; bukti penguasaan hanya dari review campuran 0012.

1. Reference, lewat Encounter (±10 menit)

Encounter adalah "An interaction between a patient and healthcare provider(s) for the purpose of providing healthcare service(s) or assessing the health status of a patient": kunjungan rawat jalan, IGD, rawat inap, kunjungan virtual. ^[4] Potongan contoh resmi (kunjungan kardiologi): ^[7]

{
  "resourceType": "Encounter",
  "id": "f001",
  "identifier": [{ "use": "official", "system": "http://www.amc.nl/zorgportal/identifiers/visits", "value": "v1451" }],
  "status": "finished",                                   // 1..1, planned | arrived | in-progress | finished | ...
  "class": { "system": "http://terminology.hl7.org/CodeSystem/v3-ActCode",
             "code": "AMB", "display": "ambulatory" },    // R4: Coding, bukan CodeableConcept
  "type": [{ "coding": [{ "system": "http://snomed.info/sct", "code": "270427003",
                          "display": "Patient-initiated encounter" }] }],
  "subject": { "reference": "Patient/f001", "display": "P. van de Heuvel" },
  "participant": [{ "individual": { "reference": "Practitioner/f002", "display": "P. Voigt" } }],
  "length": { "value": 140, "unit": "min", "system": "http://unitsofmeasure.org", "code": "min" },
  "reasonCode": [{ "coding": [{ "system": "http://snomed.info/sct", "code": "34068001",
                                "display": "Heart valve replacement" }] }],
  "serviceProvider": { "reference": "Organization/f001", "display": "Burgers University Medical Center" }
}

Tipe Reference berisi "at least one of a reference (literal reference), an identifier (logical reference), and a display (text description of target)". ^[2]

Semua contoh tabel dari halaman References. ^[2]

• Logical reference punya harga: "none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible". Kalau keduanya ada, "the literal reference is preferred". ^[2]
• Definisi elemen membatasi target: Observation.subject adalah Reference(Patient | Group | Device | Location), Encounter.subject adalah Reference(Patient | Group). ^{[5] [4]}
• Padanan JS: reference ≈ foreign key (patientId) yang ditulis sebagai path REST; display ≈ kolom nama yang di-denormalisasi supaya UI tidak perlu fetch kedua. Mengambil Patient sekaligus dengan Observation-nya (_include) dibahas di lesson 0009.

2. Observation: CodeableConcept vs Coding (±12 menit)

Ini JSON yang kemungkinan besar ditunjukkan interviewer. Contoh resmi berat badan, utuh kecuali narrative: ^[6]

{
  "resourceType": "Observation",
  "id": "example",
  "status": "final",                                       // 1..1, modifier (?!)
  "category": [{ "coding": [{ "system": "http://terminology.hl7.org/CodeSystem/observation-category",
                              "code": "vital-signs", "display": "Vital Signs" }] }],
  "code": {                                                // 1..1 CodeableConcept: APA yang diukur
    "coding": [
      { "system": "http://loinc.org",       "code": "29463-7",  "display": "Body Weight" },
      { "system": "http://loinc.org",       "code": "3141-9",   "display": "Body weight Measured" },
      { "system": "http://snomed.info/sct", "code": "27113001", "display": "Body weight" },
      { "system": "http://acme.org/devices/clinical-codes", "code": "body-weight", "display": "Body Weight" }
    ]
  },
  "subject": { "reference": "Patient/example" },           // SIAPA
  "encounter": { "reference": "Encounter/example" },       // DALAM kunjungan mana
  "effectiveDateTime": "2016-03-28",                       // KAPAN (choice type effective[x])
  "valueQuantity": {                                       // HASIL (choice type value[x])
    "value": 185, "unit": "lbs", "system": "http://unitsofmeasure.org", "code": "[lb_av]"
  }
}

Spesifikasi punya dua tipe untuk nilai berkode: ^[1]

• Coding: "a simple direct reference to a code defined by a code system": system (URI code system), version, code, display, userSelected.
• CodeableConcept: "a text description and/or a list of Codings": coding (0..*) + text (0..1).

type Coding = { system?: string; version?: string; code?: string; display?: string; userSelected?: boolean };
type CodeableConcept = { coding?: Coding[]; text?: string };

// Cari berdasarkan system, jangan coding[0]: urutan coding tidak bermakna.
const loinc = (cc: CodeableConcept) => cc.coding?.find(c => c.system === "http://loinc.org")?.code;
// Untuk UI: text dulu, lalu display coding mana pun, lalu code.
const label = (cc: CodeableConcept) => cc.text ?? cc.coding?.find(c => c.display)?.display ?? cc.coding?.[0]?.code;

Kenapa empat Coding? ^[1]

• "The concept may be coded multiple times in different code systems ... Each coding (also referred to as a 'translation') is a representation of the concept". "There is no meaning associated with the ordering of coding within a CodeableConcept."
• "A typical use of CodeableConcept is to send the local code that the concept was coded with, and also one or more translations to publicly defined code systems such as LOINC or SNOMED CT. Sending local codes is useful and important for the purposes of debugging and integrity auditing."
• Kenapa tidak cukup Coding? Pengalaman HL7: "in the general case, systems need to able to exchange multiple translation codes, and/or an original text." Coding dipakai langsung hanya bila daftar kodenya disepakati semua pihak.
• text adalah teks seperti yang dimasukkan/dipilih pengguna; kalau tidak ada coding yang userSelected, "the text (if present) is the preferred source of meaning". CodeableConcept boleh berisi text saja bila tidak ada kode yang cocok.
• Kode hanya bermakna bersama system: "coded values are always treated as a pair composed of 'system' and 'code'". ^[3] Kode H di sistem interpretasi berbeda artinya dengan H di sistem lain.

Jebakan versi: di R4, Encounter.class bertipe Coding 1..1, jadi JSON-nya objek { system, code, display } tanpa coding: [...] (lihat bagian 1). ^[4] Di R5 elemen itu menjadi CodeableConcept 0..*. ^[8] Bentuk JSON ditentukan oleh tipe di definisi, jadi baca definisinya, jangan menebak.

Ringkasan untuk dicetak: Reference: Anatomi resource + datatype · Istilah: GLOSSARY.md (bagian "Resource dan datatype")

Ada yang belum jelas? Tanyakan ke saya (agent) di terminal, misalnya: "kapan Observation memakai component alih-alih beberapa Observation?", "bagaimana mengetik resource FHIR di TypeScript tanpa menulis semuanya sendiri?", atau "apa beda ValueSet dan CodeSystem?"

Sumber (semua diakses 26 Oktober 2026): [1] Data Types · [2] Resource References · [3] Using Codes in Resources · [4] Encounter · [5] Observation · [6] Contoh Observation (berat badan) · [7] Contoh Encounter f001 · [8] Encounter (R5)