Current ICD-10 in Vietnam: Circular 06/2026/TT-BYT, Decision 1849/QĐ-BYT, and the ICD-11 outlook

1. What is ICD-10? A brief history

ICD-10 (International Classification of Diseases, 10th Revision) is the World Health Organization's tenth revision of its disease classification. The World Health Assembly (WHA) adopted ICD-10 in May 1990 and the official code set took effect on 01/01/1993. WHO stopped adding new content to ICD-10 in 2018 and shifted its focus to ICD-11 — the next-generation revision.

VN Core's ICD-10 VN CodeSystem (vn-icd10-cs) is the 2026 edition: version 2026-07-01, 16,052 concepts including multi-level codes, VN extension branches, the six WHO 2019 usage flags and bilingual coding guidance. The 2020-legacy build (15,617 codes, byte-frozen) is a pre-migration wrapper — 2020 content plus early-loaded Annex-5 additions, not a pure 2020 edition — serving only data recorded before 01/07/2026.

In Vietnam, ICD-10 has been in use since the early 2000s under several different translations. In 2020, the Ministry of Health consolidated these into a single official edition through Decision 4469/QĐ-BYT, taking ICD-10 WHO 2019 as its baseline, translating it into Vietnamese, and adding detailed branches for diseases of epidemiological significance in Vietnam.

2. Code structure: chapter, block, category, sub-category

ICD-10 is organized into four classification levels. At the top sit chapters — 22 broad disease groups numbered with Roman numerals. Each chapter contains multiple blocks, contiguous ranges of three-character codes. Each block holds three-character categories, and each category may be split into four-character sub-categories after the decimal point.

Chapter (I-XXII)        e.g., Chapter IX — Diseases of the circulatory system
   └── Block             e.g., I00-I99
       └── Category      e.g., I10 (3 characters)
           └── Sub-category   e.g., B18.0 (4 characters)
               └── VN extension   e.g., B18.00 (5 characters — only in ICD-10 VN)

A few common examples: I10 is essential hypertension, J00-J06 is the block for acute upper respiratory infections, and E11.9 is type 2 diabetes mellitus without complications. Five-character branches such as B18.00, I70.00 and J96.00 are extensions added by ICD-10 VN for selected diseases and do not exist in standard ICD-10 WHO.

3. Where ICD-10 VN diverges from ICD-10 WHO

ICD-10 VN is derived from ICD-10 WHO, but that does not make every code, display, or extension branch automatically equivalent across versions. Exchange requires both sides to identify the edition/version and use a tested comparison table or ConceptMap; the following are the principal differences.

First, Vietnamese descriptions in the national catalog. Vietnamese displays support EMR software and BHYT forms; an English display from the source version may be retained as a designation where source and licensing permit. A display is not a code identifier and does not prove semantic equivalence.

Second, five-character branch extensions for diseases common in Vietnam. Typical examples include dengue hemorrhagic fever (codes A90 and A91 are subdivided by clinical severity) and viral hepatitis B (B16 and B18 are subdivided by chronic, acute, or co-infection status). These are diseases with a high epidemiological burden in Vietnam that need finer resolution than ICD-10 WHO provides by default.

Third, epidemiology-driven supplements. Decision 98/QĐ-BYT (14/01/2022) added U07.1 and U07.2 for COVID-19. WHO had actually published these codes back in April 2020 through ICD-10 mid-cycle updates, but Vietnam formally adopted them through legal instrument only in early 2022. Clinical commentary accompanying the code set is reviewed and refreshed periodically by the Ministry of Health through separate guidance documents.

4. Decision 4469/QĐ-BYT — historical source for the 2020 edition

Decision 4469/QĐ-BYT was signed by the Minister of Health on 28/10/2020. It promulgated the then-current Vietnamese ICD-10 and ICD-9-CM catalogs. From 01/07/2026, its ICD-10 content is a historical source for the 2020 edition and provenance for legacy data only.

The Ministry of Health published two annexes alongside the decision: an Excel code catalog (with columns for Code, Vietnamese description, English description, and Notes) and a printed PDF of the full classification. The decision does not assign a SemVer-style version number, so VN Core combines the signing date with the document code (QD-4469-2020) to identify the version inside the CodeSystem.

Under the VN Core legal registry reviewed on 04/08/2026, the current authority chain is Circular 06/2026/TT-BYT plus Decision 1849/QĐ-BYT. The Circular is generally effective from 01/07/2026, with Article 5(2)–(3) effective from 01/06/2026. Decision 1849's official annexes are authoritative for content; Decisions 4469 and 98 are no longer current authority.

5. Decision 98/QĐ-BYT — historical provenance for COVID-19 codes

Decision 98/QĐ-BYT, dated 14/01/2022, added two codes to the ICD-10 VN edition then in use. From 01/07/2026 it is retained only to trace historical data; whether a code is valid for a new record must be checked directly against the current Decision 1849/QĐ-BYT edition.

• U07.1 — COVID-19, virus identified. Used when laboratory testing confirms the virus (a positive RT-PCR result or another confirmatory assay). This was the dominant code during 2022-2023 when PCR testing was widely available.
• U07.2 — COVID-19, virus not identified. Used when diagnosis rests on clinical signs and epidemiological factors, with no virological confirmation available — or none possible. This code typically appears during major outbreaks when testing capacity is overwhelmed.

In FHIR, both codes live within the same ICD-10 VN CodeSystem; no separate CodeSystem is needed. When coding a COVID-19 case, U07.1 or U07.2 occupies the primary code position. Codes for complications (COVID-19 pneumonia, post-COVID syndrome, and so on) use ordinary ICD-10 codes in secondary positions. Distinguishing U07.1 from U07.2 matters for both epidemiological statistics and BHYT settlement, since reimbursement policy may differ between the two groups.

6. ICD-9-CM Volume 3 — surgical and procedural coding

ICD-10 only classifies diagnoses; it does not code procedures. To code surgeries and procedures, the Vietnamese health sector continues to use ICD-9-CM Volume 3 (International Classification of Diseases, 9th Revision, Clinical Modification, Volume 3) — a procedure code set developed in the United States on the legacy ICD-9 base. Although the United States migrated to ICD-10-PCS in 2015, Vietnam retains ICD-9-CM Volume 3 because it is deeply embedded in the existing technical service catalog (DVKT) and DRG grouping algorithms.

Decision 387/QĐ-BYT, dated 05/02/2026, issued the 2026 edition of "International Classification of Surgeries and Procedures (ICD-9-CM)", replacing Decision 4440/QĐ-BYT (27/10/2020). Its scope covers surgical procedures, diagnostic and interventional imaging procedures, and nursing procedures. Terminology loaders should derive the code count and content directly from the official 2026 annex rather than reusing an estimate from an earlier edition.

FHIR use cases include populating Procedure.code, mapping to the Ministry of Health technical service (DVKT) catalog for BHYT reimbursement, and feeding the diagnosis-related group (DRG) algorithm. VN Core registers this CodeSystem at the canonical URL http://fhir.hl7.org.vn/core/CodeSystem/vn-icd9-cm-cs (note the hyphen between icd9 and cm, plus the -cs suffix per VN Core naming conventions).

7. ICD-11 — Vietnam status and transition requirements

The 72nd World Health Assembly adopted ICD-11 in 2019, and it came into effect on 1 January 2022. ICD-11 is designed for digital use and supports post-coordination — combining codes into clinically meaningful clusters — so transition affects policy, software, data, and coding workforce capabilities.

WHO implementation guidance states that countries may continue using ICD-10 for as long as necessary and recommends planned transition work including readiness assessment, pilots, training, and continuity of historical data. Each country's status should be checked against current WHO and national-authority sources; this page does not infer regional status from aggregate figures or assign a status to individual countries without current primary evidence.

In Vietnam, the VN Core legal registry reviewed in June 2026 does not yet include a legal instrument or formal program for ICD-11 adoption. The current implementation priority is stabilizing ICD-10 VN during the rollout of electronic medical records (Circular 13/2025/TT-BYT) and BHYT data interoperability under Decision 3176/QĐ-BYT. Any future ICD-11 transition would need versioned terminology services, tested ICD-10 ⇄ ICD-11 ConceptMaps, workforce retraining, and a pilot phase with a clearly published scope.

8. FHIR integration — canonical URIs and a Condition example

Canonical URIs (per the VNCoreConditionDiagnosis FSH)

Purpose	URI
Coding.system of the primary icd10vn slice (1..1 MS per the VNCoreConditionDiagnosis profile)	http://fhir.hl7.org.vn/core/CodeSystem/vn-icd10-cs
ICD-10 VN ValueSet binding	http://fhir.hl7.org.vn/core/ValueSet/vn-icd10-vs
Coding.system of the secondary icd10who slice (0..1 — dual-coding for international exchange)	http://hl7.org/fhir/sid/icd-10
ICD-9-CM VN CodeSystem	http://fhir.hl7.org.vn/core/CodeSystem/vn-icd9-cm-cs
SNOMED CT (international)	http://snomed.info/sct

VNCoreConditionDiagnosis uses vn-icd10-cs as the namespace of its mandatory primary coding slice (icd10vn): the Vietnamese catalogue carries its own extension branches and usage flags, so publishing it under the WHO URI would misidentify the system — the same reason Germany uses icd10gm and the US uses sid/icd-10-cm. The secondary icd10who slice (URI http://hl7.org/fhir/sid/icd-10) is for dual-coding on international exchange, generated via the vn-cm-icd10vn-to-icd10who ConceptMap. vn-icd10-vs defines the accepted code scope.

A Condition example following VNCoreConditionDiagnosis

{
  "resourceType": "Condition",
  "subject": {"reference": "Patient/vn-001"},
  "encounter": {"reference": "Encounter/enc-001"},
  "code": {
    "coding": [
      {
        "system": "http://fhir.hl7.org.vn/core/CodeSystem/vn-icd10-cs",
        "version": "2026-07-01",
        "code": "I10",
        "display": "Tăng huyết áp vô căn"
      },
      {
        "system": "http://snomed.info/sct",
        "code": "38341003",
        "display": "Hypertensive disorder"
      }
    ],
    "text": "Tăng huyết áp"
  },
  "clinicalStatus": {
    "coding": [{
      "system": "http://terminology.hl7.org/CodeSystem/condition-clinical",
      "code": "active"
    }]
  },
  "verificationStatus": {
    "coding": [{
      "system": "http://terminology.hl7.org/CodeSystem/condition-ver-status",
      "code": "confirmed"
    }]
  }
}

The version = 2026-07-01 value is the 2026 edition business version — pinned to the date the catalogue applies nationwide (Circular 06/2026/TT-BYT, Article 5), not drifting with IG releases. Data recorded before 01/07/2026 uses version = 2020-legacy on the corresponding frozen build.

The clinicalStatus and verificationStatus fields must use the exact URIs of the standard HL7 CodeSystems — http://terminology.hl7.org/CodeSystem/condition-clinical for active and http://terminology.hl7.org/CodeSystem/condition-ver-status for confirmed. FHIR R4 binds both with required strength; placeholder URIs will fail validation.

9. Mapping design for ICD-10 VN, ICD-10 WHO, and SNOMED CT

VN Core v0.9.0 already includes a draft ConceptMap from ICD-10 VN to SNOMED CT, plus related ConceptMaps for CLS-to-LOINC, BHYT financial fields to adjudication, and legacy-to-new province mapping. The layers below should be read as a design stack, not as three fully completed artifacts in the same release.

• vn-cm-icd10vn-to-icd10who — maps the five-character VN extension codes back to their corresponding four-character ICD-10 WHO codes. This ConceptMap is needed when Vietnamese data is sent to international systems (WHO epidemiological reporting, multi-country research).
• vn-cm-icd10-to-snomed — the current draft artifact selectively maps 143 ICD-10 VN source codes to SNOMED CT. Relationship is stated per element; this one-way artifact implies neither a reverse map nor equivalence outside its scope.
• xml4210-to-fhir-condition — a design layer for mapping an XML diagnosis field to a Condition carrying ICD-10 VN. It does not replace the current XML channel; an implementation must define source/target versions, error handling, and integration tests against the BHXH workflow.

The ConceptMaps in VN Core v0.9.0 remain draft artifacts and should be piloted with real hospital data before they are treated as mandatory conformance. Decision 2427/QĐ-BYT (SNOMED CT VN Batch 1, Body Structure) and batches 2-3 are the primary source data for the SNOMED CT mapping.

Every dual-coding flow must declare source and target systems and versions, scope, mapping direction, and the per-element R4 ConceptMap equivalence. Never assume two codes are equivalent: test common codes, extension branches, one-to-many and unmapped cases, and round-trip behavior before using a map for reporting, clinical decisions, or reimbursement.

10. FAQ

Can ICD-10 WHO be used instead of ICD-10 VN?

This cannot be answered from the code string alone. Check the profile, legal workflow, and catalog version required by the receiver; a Vietnamese extension branch may not exist in the target WHO edition. Send dual coding only after declaring system/version, mapping direction and relationship in a ConceptMap, and testing the map with representative data. Two entries in one CodeableConcept do not by themselves prove equivalence.

ICD-11 is coming — should we wait?

No, not if your project is implementing EMR or BHYT workflows now. The VN Core legal registry reviewed in June 2026 does not yet include an ICD-11 roadmap for Vietnam. The safer approach is to implement ICD-10 VN properly today while designing your terminology server with versioning and ConceptMaps so a future official transition remains possible.

Do we need to install ICD-10 VN into our database?

Yes: load vn-icd10-cs 2026 edition (version 2026-07-01, 16,052 concepts — fully reconciled against the signed Circular 06/2026/TT-BYT table and Annexes 4–5 of Decision 1849/QĐ-BYT). Redistribution rights for production deployments still follow the IG's release gate. HAPI FHIR JPA Server can serve $lookup and $validate-code after the source has been verified.

Does Decision 4469 ship with an Excel file?

Yes, but that file is a source for the 2020 edition only. It is not the current source after 01/07/2026; a production edition must be built from and reconciled against the official Decision 1849/QĐ-BYT annexes.

How long will the COVID-19 codes U07.1 and U07.2 stay in use?

Do not infer current status from Decision 98/QĐ-BYT, which is now legacy provenance. Implementations must check U07.1/U07.2 in the Decision 1849/QĐ-BYT annexes and apply Circular 06/2026/TT-BYT for the relevant data period.

11. References and further reading

Vietnamese legal documents

• Circular 06/2026/TT-BYT — current ICD-10 coding authority; generally effective 01/07/2026, with Article 5(2)–(3) effective 01/06/2026. Document code: TT-06-2026.
• Decision 1849/QĐ-BYT (23/06/2026) — technical guidance and authoritative annexes for the current edition. The exact official decision page and complete official Annex 5 still need to be secured and reconciled in the corpus.
• Decision 4469/QĐ-BYT (28/10/2020) — 2020 edition; legacy provenance only from 01/07/2026. Document code: QD-4469-2020.
• Decision 98/QĐ-BYT (14/01/2022) — COVID-19 addition to the former edition; legacy provenance only from 01/07/2026. Document code: QD-98-2022.
• Decision 387/QĐ-BYT (05/02/2026) — 2026 edition of the ICD-9-CM international classification of surgeries and procedures, replacing Decision 4440/QĐ-BYT. Document code: QD-387-2026.
• Full lookup at the VN Core Legal Corpus page.

International references

• WHO — Classification of Diseases (ICD-10 and ICD-11 history).
• WHO — WHA72 adoption of ICD-11 (adopted in 2019, effective 1 January 2022).
• WHO — ICD-11 implementation FAQ (transition principles and planning).
• ICD-10 WHO 2019 Browser — the upstream baseline for ICD-10 VN.
• FHIR R4 — Condition Resource (definition of clinicalStatus, verificationStatus, and binding constraints).
• HL7 FHIR — ICD-10 Code System (URI http://hl7.org/fhir/sid/icd-10).
• SNOMED International — SNOMED CT for cross-mapping.

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