Frequently Asked Questions — HL7, FHIR, VN Core IG

HL7 basics (Q1–Q10)

Q1. What is HL7?

HL7 (Health Level Seven International) is a non-profit health data standards organization founded in 1987 in the United States. The name "Level 7" refers to the Application layer of the OSI model. Prominent product families include HL7 v2, the RIM-based HL7 v3 family, CDA, and FHIR. Read the full article: "What is HL7".

Q2. Are HL7 and FHIR the same thing?

No. HL7 International develops multiple product families: HL7 v2 focuses on messages, the v3 family is RIM-based, CDA defines clinical documents, and FHIR uses Resources while supporting REST, documents, messages, and operations. When people say "HL7" in technical contexts, they often mean HL7 v2 specifically.

Q3. Does Vietnam have an HL7 Affiliate yet?

In the public affiliate lists reviewed in June 2026, the project did not identify an official HL7 Affiliate in Vietnam. The trial-use initiative hl7.org.vn, launched by Omi HealthTech, is preparing technical and governance foundations so stakeholders can assess an Affiliate path. Establishment and the filing entity require a separate consensus decision, HL7 International eligibility, and the relevant authority.

Q4. Is HL7 free?

Many published HL7 standards are available without charge under their applicable IP policy. FHIR core is CC0, but terminologies, IGs, and third-party dependencies retain their own license terms. Membership, voting, education, certification, events, and some services have separate eligibility or fees.

Q5. Is HL7 v2 obsolete?

No. HL7 v2 remains common in long-running ADT (Admit/Discharge/Transfer), laboratory, pharmacy, and imaging interfaces. Coexistence with FHIR depends on integration contracts and system lifecycles; no global adoption percentage or replacement date applies to every country.

Q6. Is HL7 v3 still in use?

HL7 v3 remains present in some systems and underpins CDA, but its new-implementation ecosystem is smaller than FHIR's and HL7 v2's. A greenfield project should choose a standard from its use case, regulation, partner contracts, and operating capability; FHIR is not superior on every criterion by definition.

Q7. What is CDA?

CDA (Clinical Document Architecture) is an HL7 v3-based clinical-document standard used for discharge summaries, referral letters, and other records. CDA and FHIR documents based on Composition/Bundle can coexist; the target IG and exchange contract determine which model applies.

Q8. Who uses HL7 in Vietnam?

Some private hospitals, tertiary hospitals, and international PACS/LIS vendors have implemented HL7 v2 or healthcare API integration patterns inside their own systems. There is no Vietnamese legal mandate for HL7 yet, but Circular 13/2025/TT-BYT on electronic medical records opens the door for FHIR adoption.

Q9. Where can I learn HL7?

The official spec lives at hl7.org. Hands-on training is widely available through vendors such as Mirth Connect and HAPI FHIR. HL7 International also runs accredited online courses. A Vietnamese-language community is taking shape at hl7.org.vn.

Q10. How do HL7 and DICOM differ?

HL7 carries text-based data: ADT, lab, prescriptions, and clinical records. DICOM carries medical imaging: X-ray, CT, MRI, and ultrasound. The two standards complement each other rather than competing. FHIR's ImagingStudy resource links to a DICOM Study UID.

FHIR basics (Q11–Q20)

Q11. What is FHIR?

FHIR (Fast Healthcare Interoperability Resources) is HL7's healthcare data-exchange standard. It is commonly used through RESTful HTTP with JSON or XML, while also supporting documents, messages, and other exchange paradigms. DSTU1 was published in 2014. The phrase "80/20" describes a FHIR design heuristic: keep the core resources useful for common situations and use extensions for valid requirements outside the core. It is not a measured coverage ratio, and extensions still require canonical definitions and governance. Read the full article: "What is FHIR".

Q12. How is FHIR pronounced?

Pronounced "fire" /faɪər/ — the same as the English word for flames. Avoid spelling out the letters as "F-H-I-R".

Q13. How many Resources are in FHIR?

FHIR R4 (4.0.1) defines 146 Resources mixing Normative and STU (Standard for Trial Use) levels. A subset has reached stable Normative status (Patient, Observation), while others remain Trial Use and may receive minor adjustments in future versions.

Q14. Which FHIR version should I use?

VN Core currently uses R4 (4.0.1) as its baseline; other projects must select a version based on the target IG, package dependencies, and the participating endpoints' CapabilityStatement resources. R5 (5.0.0) is the latest published major release and remains Trial Use; R6 is currently a CI/ballot build, not a stable release. See the FHIR version comparison.

Q15. Does FHIR use JSON or XML?

JSON and XML are both standard FHIR R4 formats, negotiated through media types. Specific support, including RDF/Turtle, must be verified in the deployed product's CapabilityStatement and documentation.

Q16. Will FHIR replace HL7 v2?

There is no global replacement schedule. Many organizations run HL7 v2 for established internal interfaces and FHIR for APIs or exchanges governed by newer IGs. Retiring v2 requires an interface inventory, partner readiness, and a tested migration plan.

Q17. Is FHIR free?

Yes. The FHIR specification is published under CC0. Both open-source implementations and commercial services exist; actual cost depends on infrastructure, traffic, storage, security, operations, and support rather than licensing alone.

Q18. Where can I find a public FHIR sandbox?

HAPI FHIR and Firely offer public test endpoints, but URLs, versions, retained data, and capabilities can change; inspect current metadata and terms before use. These are public test environments: never send PHI, national identifiers, BHYT data, or real patient records.

Q19. What is SMART on FHIR?

SMART App Launch is an Implementation Guide that profiles OAuth 2.0 discovery, authorization, launch context, and scopes for FHIR applications; OpenID Connect may support user identity where the advertised capability permits it. Token authorization does not itself establish legal consent: the processing basis and permission experience must be determined separately for the use case.

Q20. How do FHIR and openEHR differ?

They address different layers. FHIR is an exchange standard supporting REST, documents, messages, and other paradigms; openEHR is a record-modeling and persistence platform built around archetypes and templates. They can be combined when the API contract, mappings, and round-trip tests are defined explicitly. Read the full comparison.

VN Core IG (Q21–Q30)

Q21. What is VN Core IG?

The VN Core IG at fhir.hl7.org.vn is the project's trial-use FHIR R4 Implementation Guide for the Vietnamese healthcare context; it is not yet a national standard or an HL7 International-approved publication. It contains Profiles (Patient, Encounter, Coverage, Claim, etc.), Extensions (ethnicity, BHYT, level of care), and Terminology (ICD-10 VN, the 34 provinces, the 54 ethnic groups, and more). See the about page.

Q22. What is the current VN Core IG version?

Version 0.8.0 (Draft for Community Review, July 2026). It is the milestone preceding the release candidate. The 1.0.0 roadmap points to Q3 2027 after sufficient evidence from publicly disclosed or review-eligible pilots and Working Group review.

Q23. Where is the VN Core IG repository?

There are two main sources: the Ministry of Health IT Department repo at github.com/hl7vn/vn-core-ig (a 2024 draft, infrequently updated), and the Omi HealthTech trial-use artifact set at github.com/HL7-org-vn (under active development). The long-term goal is to bring both branches into a shared comparison and governance process.

Q24. What is the canonical URL for VN Core?

Community canonical URL: http://fhir.hl7.org.vn/core/. The previous Ministry of Health build used http://fhir.ehealth.gov.vn/core/. Canonical convergence should go through the Working Group and a formal governance decision.

Q25. Which Profiles are in VN Core IG?

VN Core v0.9.0 ships 86 Profiles: VNCorePatient, VNCorePractitioner, VNCoreOrganization, VNCoreEncounter, VNCoreCondition, VNCoreObservation, VNCoreCoverage, VNCoreClaim, VNCoreExplanationOfBenefit, VNCoreMedicationRequest, VNCoreQuestionnaire, VNCoreQuestionnaireResponse, VNCoreFamilyMemberHistory, VNCoreAllergyIntolerance, VNCoreComposition, and VNCoreBundleIPS. All of them follow the naming convention VNCore{Resource}.

Q26. Which Extensions does VN Core IG provide?

VN Core v0.9.0 publishes 56 Extensions: 53 Vietnam-specific extensions and 3 reused official HL7 Patient extensions. The local set covers ethnicity (54 groups), commune/ward (3,321 units after Resolution 202/2025/QH15), BHYT card details (beneficiary class, registration site, validity), level of care, hospital rank, practitioner license number, academic title, and legacy administrative codes.

Q27. Which CodeSystems does VN Core IG cover?

VN Core v0.9.0 contains 165 CodeSystems and 168 ValueSets: ICD-10 VN (Decision 4469/QĐ-BYT), ICD-9-CM 2026 (Decision 387/QĐ-BYT), the 54 ethnic groups, the 34 provinces (Resolution 202/2025/QH15), BHYT beneficiary classes (Decision 3276/QĐ-BYT), levels of care, hospital ranks, partial LOINC, SNOMED CT VN (three releases), traditional Vietnamese medicine (Decisions 2552/QĐ-BYT and 3080/QĐ-BYT), and many other domain-specific code sets.

Q28. Can I contribute to VN Core IG?

Yes. The project is published under CC-BY-4.0 and currently receives structured technical proposals via [email protected] while the public tracker is not yet open. Welcome contributions include new profiles, real-world business extensions, test data, documentation translations, and evidence-backed bug reports. See the governance model.

Q29. Does VN Core conflict with the Ministry of Health IG?

No. The two drafts serve the same national FHIR-standardization goal but have different canonical URLs and governance. The state-published build uses http://fhir.ehealth.gov.vn/core/; the fhir.hl7.org.vn build is a trial-use draft maintained by Omi HealthTech. Any canonical convergence or official recognition should go through a Working Group and formal governance decision.

Q30. When will VN Core 1.0 ship?

Planned roadmap: a Q4 2026 release candidate (RC1) if sufficient implementation evidence is available, followed by a more stable trial-use 1.0.0 in Q3 2027. Every milestone may shift based on implementation evidence, governance decisions, and any formal feedback received.

BHYT & XML 4210 (Q31–Q35)

Q31. Is XML 4210 still in use?

Yes, according to the VN Core legal registry reviewed in June 2026. Note, however, that "XML 4210" is a legacy shorthand based on the older Decision 4210/QĐ-BYT. The current legal basis for the data standard submitted to Vietnam Social Security (BHXH) is Decision 130/QĐ-BYT, amended by Decision 4750/QĐ-BYT, and most recently Decision 3176/QĐ-BYT (29/10/2024). Formal technical documents should refer to it as Decision 3176.

Q32. Will FHIR replace XML 4210?

There is no formal regulation mandating a replacement. Decree 164/2025/NĐ-CP governs electronic transactions in social insurance but does not prescribe FHIR. FHIR is one option to evaluate against the destination's endpoints, payloads, governance, and integration contract.

Q33. How do I map XML 4210 to FHIR?

Coverage, Claim, and ExplanationOfBenefit are reference modeling points, not one-to-one equivalents of the complete BHYT schema. Field and structural conversion requires a versioned, tested mapping specification or adapter; ConceptMap is limited to code/concept relationships in coded fields. VN Core currently ships 14 ConceptMaps, including the priority BHYT financial-field → adjudication (vn-cm-bhyt-financial-field-to-adjudication) and cost-group → cost-category (vn-cm-bhyt-claim-cost-group-to-cost-category) maps. Read the article: "FHIR and BHYT".

Q34. What is new in Decision 697/QĐ-BYT?

Decision 697/QĐ-BYT, issued 19/03/2026, defines the new BHYT cost itemization template with 12 categories, 13 columns, and multi-BHYT support (multiple cards on a single encounter). It took effect on 19/03/2026; the transition and software-upgrade window closed on 01/07/2026 — it is now the sole template. It fully supersedes Decision 6556/QĐ-BYT (2018); the old template is only kept to cross-check records created before 01/07/2026.

Q35. Does Decree 188/2025 set a universal payment cap?

No. Decree 188/2025/NĐ-CP (effective 15/08/2025) sets caps and benefit levels per cost category (medications, medical supplies, technical procedures, hospital beds), not a single universal number for Claim.total. VN Core uses the cumulativeCopay extension to model running co-payment totals; detailed caps and benefit levels live in the rules engine or the BHXH integration gateway, not in base profile invariants.

Legal framework (Q36–Q42)

Q36. What does Circular 13/2025/TT-BYT require?

Article 1(3) of Circular 13/2025/TT-BYT (effective 21/07/2025) requires EMR information to be linked to the personal identification number of Vietnamese citizens and of foreign nationals who have been issued an electronic identification account; these are not two alternative identifiers. The system must also meet applicable infrastructure, security, retrieval, electronic-transaction, and signature rules. Timelines: hospitals by 30/09/2025; other healthcare facilities by 31/12/2026.

Q37. What does Decree 278/2025/NĐ-CP require?

Decree 278/2025/NĐ-CP mandates data connection and sharing between government agencies and information systems. It took effect on 22/10/2025 (the date of issue). Standardization and unified connections must be in place by 31/12/2026. Its effect on a health system depends on whether that system falls within the decree's regulated actors, data, and connections.

Q38. What does Personal Data Protection Law 91/2025 cover?

The Personal Data Protection Law (Law 91/2025/QH15, effective 01/01/2026) classifies health data as sensitive personal data. Lawful basis, impact assessment, data-protection personnel, audit, and breach-notification duties must be determined from the processing role, scope, and incident; not every obligation is triggered identically for every system. Read the article: "FHIR and the Personal Data Protection Law".

Q39. Does Decree 356/2025 replace Decree 13/2023?

Yes. Decree 356/2025/NĐ-CP (effective 01/01/2026) fully supersedes Decree 13/2023/NĐ-CP. Every new technical and legal document must reference Decree 356/2025; do not cite the now-defunct Decree 13/2023. Decree 356/2025 provides the detailed implementation rules for Law 91/2025.

Q40. Does AI Law 134/2025 apply to healthcare AI?

Potentially. The AI Law (Law 134/2025/QH15, effective 01/03/2026) applies a risk-classification framework, but a system should not be assigned a tier solely because it is used in healthcare. Assess its intended purpose, impact, and statutory criteria; registration, assessment, and human-oversight duties follow that classification. Read the article: "FHIR and the AI Law".

Q41. What does Decree 90/2026 penalize?

Decree 90/2026/NĐ-CP covers administrative penalties in the health sector (effective 15/05/2026). Specific penalty amounts for EMR compliance and data interoperability should be checked directly against the decree text for each concrete case; do not extrapolate beyond the issued provisions.

Q42. Can personal data be stored outside Vietnam?

It may be permitted, but the organization must determine its cross-border-transfer impact-assessment duties under Law 91/2025/QH15 and Decree 356/2025/NĐ-CP, including any statutory exemptions. Server location is one assessment factor; hosting in Vietnam does not establish compliance by itself, and offshore hosting cannot be decided from a generic FAQ alone.

Hospital implementation (Q43–Q50)

Q43. Do small hospitals need FHIR?

The need depends on the interoperability contracts the hospital must satisfy. A smaller facility can begin with one workflow and one actor profile rather than a complete platform. A stable internal interface need not be replaced against a generic deadline; the roadmap should follow concrete use cases and exchange partners.

Q44. What is the cost estimate for a Class II hospital?

Hospital class alone is insufficient for a defensible estimate. Assess source systems, interface count, data quality, terminology scope, security and SLA requirements, build-versus-buy choices, and acceptance criteria. Separate one-time delivery, recurring operations, and migration contingency in the estimate. See the article: "For hospital CIOs".

Q45. Can I self-host a FHIR server?

Yes. HAPI FHIR and other products support self-hosting, but an open-source license does not remove compute, database, backup, monitoring, security, upgrade, and on-call costs. Hosting location is only one legal factor; self-hosting does not by itself prove data-residency or personal-data compliance.

Q46. Which FHIR vendors operate in Vietnam?

Some major international vendors ship FHIR modules in their global products. In Vietnam, each HIS/EMR/LIS capability should be confirmed project by project through a CapabilityStatement, test payloads, and validator results. hl7.org.vn currently discloses 0 public confirmed pilots; confidential pilots are not listed until naming is approved.

Q47. How long does HL7 v2 to FHIR migration take?

There is no standard duration. Estimate from interface count, v2 customization, terminology, historical data, partner coordination, and parallel-run requirements. Migrating workflow by workflow with reconciliation and rollback criteria is usually safer than selecting one universal cutover date; retire v2 only after every dependent party is ready.

Q48. Do I have to replace my current EMR?

Not necessarily. A FHIR façade can fit a viable legacy backend; native integration or replacement can fit other contexts. Base the decision on the data model, vendor change capability, dual-operation cost, and system lifecycle rather than one default pattern.

Q49. How long does FHIR EMR training take for clinicians?

Clinicians usually do not need FHIR syntax; training focuses on the UI and workflow. Determine duration through workflow-impact assessment, user roles, and usability pilots. FHIR can remain technical infrastructure while data-flow changes still affect entry, review, and correction tasks.

Q50. How do I join the VN Core IG community?

Website: hl7.org.vn. Email: [email protected]. Visit the community page for additional discussion channels and events.

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