EMR data migration has long been blocked by one main wall: "each product uses its own proprietary format, so data cannot be moved as-is." With the progress of medical DX (digital transformation), however, "EMR information standardization (the standard requirements)"—handling EMR information via standard specifications—is being developed, and the way we think about migration is changing. This article organizes methods, steps, and limitations of EMR data migration aligned with the standard requirements, based on official information from the Ministry of Health, Labour and Welfare (MHLW).
Disclaimer: This article provides general information. Because programs, standard specifications, launch timing, and medical fees can change through revisions/notices, always confirm the latest primary sources (MHLW notices and official materials) in practice.
Why "Standard Requirements" Change Data Migration
Traditional EMRs stored patient data in vendor-specific data structures. As a result, switching required individually converting exported data into the new chart's format, creating risks of cost, time, and data loss. The reason free-text progress notes can often only be carried over as "reference-only PDFs" is precisely this proprietary format (for migration basics, see The Complete Guide to EMR Data Migration and Switching).
In contrast, medical DX (the Nationwide Medical Information Platform / the EMR Information Sharing Service) assumes that EMR information is structured with standard specifications. If data can be held and exported in standard formats from the start, the cost of vendor-to-vendor conversion drops, easing so-called vendor lock-in. In other words, "the degree of conformance to the standard requirements" increasingly determines how easy future migration will be.
Three Specifications to Know in the EMR Standard Requirements
The following three are central to EMR information standardization. When thinking about migration, be sure to master these three terms.
1. HL7 FHIR (Standard for Information Exchange)
HL7 FHIR is an international standard for exchanging medical information. The EMR Information Sharing Service exchanges information such as diagnoses, allergies, and prescriptions in FHIR format. Because it can function as a common language not only for inter-institution collaboration but also for chart-to-chart data handoff, it is important from a migration standpoint too.
2. SS-MIX2 (Standardized Storage)
SS-MIX2 is a "standardized storage" mechanism that accumulates EMR clinical data as files in a standard format, adopted as an MHLW standard specification. It can store structured data such as prescriptions, tests, and injections in a standard format, and has been used for portability in regional collaboration, BCP (disaster preparedness), and system migration. If the old chart supports SS-MIX2 output, extracting data at migration becomes realistic.
3. Standard Codes (Code Harmonization)
As a prerequisite for handling information in a standard format, registering each item with standard codes is essential. Representative examples are as follows:
| Information | Main standard codes (examples) |
|---|---|
| Diagnoses | ICD-10-linked standard disease-name master, codes for the receipt (rezept) computer-processing system |
| Drugs | HOT codes, YJ codes |
| Tests | JLAC10 / JLAC11 (clinical laboratory test classification codes) |
Free text as-is cannot be migrated or shared in a standard way. Operating so that the six information categories (diagnoses, allergies, contraindicated drugs, infectious diseases, tests, prescriptions) are registered with standard codes determines the effectiveness of standardization (for the full picture of sharing, see Complete Guide to the EMR Information Sharing Service).
The Relationship Between the Standard-Type EMR and Migration
MHLW is developing a cloud-based standard-type EMR, mainly for small medical institutions. The standard-type EMR is oriented to be designed on the premise of conformance to the EMR Information Sharing Service and standard specifications, and is being rolled out in stages after model projects (confirm the latest target scope and timing in official information).
Between charts that conform to standard specifications, structured data such as the six information categories becomes easier to hand off via standard formats. When choosing a migration destination, it is useful to add "how far that chart conforms to the standard requirements (HL7 FHIR / standard codes / SS-MIX2, etc.)" to your evaluation criteria for ease of migration.
Main Methods of Data Migration Aligned with the Standard Requirements
1. Migration via Standardized Storage (SS-MIX2)
If the old chart can accumulate and export standardized data via SS-MIX2, this method imports those standard files into the new chart. Because structured data such as prescriptions and tests can be handed off in a standard format, it tends to suppress interpretation mismatches compared with proprietary-format conversion. However, it depends on the old chart's support status and output scope.
2. Migration of Structured Data via Standard Codes
Data held with standard codes for diagnoses, drugs, tests, and so on can be imported into the new chart under the same code system, reducing mapping effort and the risk of mis-conversion. Conversely, if the old chart operated only with proprietary codes, code conversion (reconciliation) to standard codes is required.
3. Data Handoff via HL7 FHIR
In the future, between environments that can export/import in FHIR format, handing off standard items becomes easier. Because the supported scope currently differs by product and item, it is important to concretely confirm what range can actually be used for migration.
4. Combined Use with Traditional Methods (Free Text/Images as Reference PDFs)
What the standard requirements cover is mainly structured data. Free-text progress notes, schemas, images, and the like are realistically carried over as reference-only PDFs and similar. Design by separating "the parts that can be moved in standard specifications" from "the parts retained for reference as PDFs, etc."
Migration Steps Considering the Standard Requirements
- Inventory the current chart's standard support: check for SS-MIX2 output, standard-code operation, and FHIR support
- Inspect standard-coding of the six information categories: whether diagnoses, drugs, and tests are registered with standard codes (proprietary codes are conversion targets)
- Separate the migration scope: distinguish structured data to move via standards from free text/images to retain as reference PDFs, etc.
- Present requirements to old/new vendors and obtain estimates: confirm feasibility of standard-format output/import and cost in writing
- Test migration and reconciliation: verify with a subset of data, including the correspondence of standard codes
- Parallel operation and statutory retention: keep the old chart referenceable right after switching, and meet the obligation to retain medical records (in principle, 5 years)
Easily Overlooked Cautions and the "Limits of Standardization"
- Standardization is not a cure-all: what the standard requirements mainly target is structured data such as the six information categories; it does not seamlessly move free text or proprietary documents in the chart body. Excessive expectations are unwise.
- It depends on the old chart's support status: because the standard requirements are a new framework, older environments may not yet support SS-MIX2 output or standard-code operation. First confirm whether data "can be extracted."
- Security and guideline compliance: because patient information is handled even during migration, handling in line with the "Guidelines for the Safe Management of Medical Information Systems" (the Three Ministries' Two Guidelines) is required (for practice, see Practical Steps for Three Ministries' Two Guidelines Compliance).
- Confirm primary sources: the version, target scope, and timing of standard specifications are updated. When implementing, confirm the latest definitions in MHLW's official materials.
The AI-native EMR "AI Karte" manages patient information, diagnoses, and claim (rezept) data on a single foundation with an integrated receipt computer (rececon), operating in a cloud environment compliant with the Three Ministries' Two Guidelines. Designed with an eye on the flow of medical-DX standardization, its AI summarization makes it easier to grasp past charts even after migration, reducing the burden right after switching. Its standard-conformance status and the feasibility and scope of migration can be discussed according to your individual environment.
Conclusion
Conforming to the EMR standard requirements (HL7 FHIR, SS-MIX2, standard codes) brings data migration closer from "reliance on proprietary-format conversion" to "handoff in a standard format," raising future ease of switching. At the same time, what standardization covers is mainly structured data, and free text and images still require the usual ingenuity. Separating the parts that can be moved by standards from the parts retained for reference—this design is the key to succeeding at migration in the age of standards.
Through providing AI Karte, Pottech aims to be the ideal business partner for clinics—improving the working environment for physicians, nurses, and medical clerical staff, and supporting clinics in fully realizing what they want to achieve.
For more details, please feel free to contact us.
References
- EMR Information Sharing Service (Ministry of Health, Labour and Welfare)
- On Standard Specifications (HS) in the Health and Medical Information Field (Ministry of Health, Labour and Welfare)
- Guidelines for the Safe Management of Medical Information Systems, Ver. 7.0 (Ministry of Health, Labour and Welfare)