ICD-10 Vietnam edition: Decision 4469/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.

The full code set contains roughly 14,000 three- and four-character codes organized into 22 chapters (Chapter I through XXII) by disease group and cause. ICD-10 serves three main purposes: classifying diseases in medical records, reporting epidemiological and mortality statistics, and grounding health insurance reimbursement. Vietnam uses ICD-10 for all three, with its role as the diagnosis coding standard for BHYT (social health insurance) reimbursement being the central use case.

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., I10.0 (4 characters)
               └── VN extension   e.g., I10.00 (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 I10.00 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 preserves 100% of the three- and four-character code catalog from ICD-10 WHO, so international and Vietnamese codes can be exchanged without conflict. The differences come down to three points.

First, Vietnamese translations for every description. Each code carries a unified Vietnamese display used by both EMR (electronic medical record) software and BHYT billing forms. The original WHO English display can still be retained as a secondary designation in the CodeSystem.

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 — the founding document

Decision 4469/QĐ-BYT was signed by the Minister of Health on 28/10/2020. It promulgated both the "International Classification of Diseases and Causes of Death (ICD-10)" and the "International Classification of Surgeries and Procedures (ICD-9-CM)" for use across all healthcare facilities nationwide. The ICD-10 portion is the original ICD-10 VN edition referenced throughout this document.

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.

As of April 2026, Decision 4469 remains in force. However, on 02/04/2026 the Ministry of Health issued Circular 06/2026/TT-BYT on ICD-10 coding, with effect from 01/07/2026. The circular specifies the principles for selecting primary and secondary codes and the quality assurance process for coding. VN Core lists TT-06-2026 in VNLegalDocumentRefCS with status future-effective, allowing implementation teams to prepare appropriate Must Support constraints in advance of the effective date.

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

Decision 98/QĐ-BYT, dated 14/01/2022, added two codes to ICD-10 VN for SARS-CoV-2 disease. It was Vietnam's legal response to WHO's mid-cycle update during the pandemic.

• 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, with roughly 3,000 codes (estimated based on previous editions).

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 — why Vietnam has not adopted it yet

WHO published ICD-11 in 2018 and the official code set took effect on 01/01/2022. Unlike ICD-10's linear short alphanumeric structure, ICD-11 uses an ontology-based architecture that allows a single code to have multiple parents and supports post-coordination — combining several codes into clusters with their own clinical meaning. The structure is far more expressive but demands significant changes to software and to the coding workforce.

Global ICD-11 adoption through 2026 remains narrow — fewer than 30 countries have implemented it formally inside their national health systems, despite WHO's encouragement to migrate from 2022 onward. Japan, South Korea, and most of Europe still keep ICD-10 as the legal standard while studying gradual transition pathways.

In Vietnam, as of April 2026, no legal instrument or formal program has been issued for ICD-11 adoption. The Ministry of Health has prioritized 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. Mapping ICD-10 ⇄ ICD-11 has to be completed before any switchover, and that is a substantial terminology ConceptMap effort. A reasonable scenario has Vietnam piloting ICD-11 at a handful of central hospitals around 2027-2028 before any nationwide rollout.

8. FHIR integration — canonical URIs and a Condition example

Canonical URIs (per the VNCoreConditionDiagnosis FSH)

Purpose	URI
Coding.system in Condition.code (per the VNCoreConditionDiagnosis profile)	http://hl7.org/fhir/sid/icd-10
ICD-10 VN ValueSet binding	http://fhir.hl7.org.vn/core/ValueSet/vn-icd10-vs
VN ICD-10 CodeSystem metadata wrapper	http://fhir.hl7.org.vn/core/CodeSystem/vn-icd10-cs
ICD-9-CM VN CodeSystem	http://fhir.hl7.org.vn/core/CodeSystem/vn-icd9-cm-cs
SNOMED CT (international)	http://snomed.info/sct

The reasoning: the VNCoreConditionDiagnosis profile constrains Coding.system to the international HL7 URI (http://hl7.org/fhir/sid/icd-10) to guarantee interoperability with FHIR systems outside Vietnam. The ValueSet vn-icd10-vs enumerates exactly the set of ICD-10 VN codes that may be used (the WHO codes plus the VN extension branches). The CodeSystem vn-icd10-cs serves as a metadata wrapper — carrying the Vietnamese display and additional ICD-10 VN attributes — and is not used as the URI inside instances.

A Condition example following VNCoreConditionDiagnosis

{
  "resourceType": "Condition",
  "subject": {"reference": "Patient/vn-001"},
  "encounter": {"reference": "Encounter/enc-001"},
  "code": {
    "coding": [
      {
        "system": "http://hl7.org/fhir/sid/icd-10",
        "code": "I10.0",
        "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 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. ConceptMap: ICD-10 VN ⇄ ICD-10 WHO ⇄ SNOMED CT

VN Core plans to publish three ConceptMaps to support data integration across systems.

• vn-icd10-to-icd10-who — 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-icd10-to-snomed-ct — selectively maps a subset of ICD-10 VN codes to SNOMED CT to take advantage of SNOMED's higher clinical resolution. The mapping is one-to-many in the VN → SNOMED direction and many-to-one in the reverse direction; it applies only to a core clinically meaningful set.
• xml4210-to-fhir-condition — maps the diagnosis-code field in XML 4210 (the BHXH data exchange standard) to a FHIR Condition carrying an ICD-10 VN Coding. This ConceptMap acts as a bridge so hospitals currently submitting to BHXH via XML 4210 can transition to FHIR without disrupting the reimbursement pipeline.

All three ConceptMaps will ship in draft status with VN Core v0.1.0 and iterate based on community feedback. Decision 2427/QĐ-BYT (SNOMED CT VN Batch 1, Body Structure) and the subsequent batches 2-3 will serve as the primary data source for the SNOMED CT mapping.

10. FAQ

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

Technically yes, since ICD-10 VN preserves 100% of the WHO code set. However, BHYT reimbursement records and statutory health statistics require ICD-10 VN — the Vietnamese display and certain five-character codes only exist in the VN edition. The recommended practice is to attach two Coding entries inside Condition.code: one international (WHO) and one VN.

ICD-11 is coming — should we wait?

No. ICD-11 has no official roadmap in Vietnam, and any transition would take at least 2-3 years of preparation. Investing in ICD-10 VN today is the right call for at least the next five years.

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

Yes. To support lookup, autocomplete, and validation inside EMR software, the full ICD-10 VN CodeSystem needs to be loaded into a FHIR terminology server or an application database lookup table. HAPI FHIR JPA Server can load the CodeSystem JSON and serve $lookup and $validate-code directly.

Does Decision 4469 ship with an Excel file?

Yes. The Ministry of Health published an Excel code catalog alongside Decision 4469, downloadable from the Ministry of Health portal or various online legal libraries. The Excel file is the source of truth for building the FHIR CodeSystem.

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

Both codes remain in force and will continue to be used for every COVID-19 case, regardless of pandemic status. WHO has set no expiration for them.

11. References and further reading

Vietnamese legal documents

• Decision 4469/QĐ-BYT (28/10/2020) — Vietnam edition of the ICD-10 international classification of diseases and ICD-9-CM. VN Core document code: QD-4469-2020.
• Decision 98/QĐ-BYT (14/01/2022) — Adds COVID-19 codes (U07.1, U07.2) to ICD-10 VN. 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.
• Circular 06/2026/TT-BYT (issued 02/04/2026, effective 01/07/2026) — Regulates ICD-10 coding. Document code: TT-06-2026. Status: future-effective.
• Full lookup at the VN Core Legal Corpus page.

International references

• WHO — Classification of Diseases (ICD-10 history, ICD-11 roadmap).
• 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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