Overview
ISO/TS 24289:2021 - Health informatics - Hierarchical file structure specification for secondary storage of health-related information - defines a simple, vendor-neutral directory and file-identifier model for storing health data on secondary file systems. The specification prescribes a hierarchical folder layout and naming rules that use metadata (for example Patient ID, transaction date, and contents description) to organize clinical transactions and documents without requiring a database engine. It supports HL7 Ver2.5 (ISO/HL7 27931:2009) message files as well as common document types (XML, CDA, DOC/DOCX, PDF, XLS/XLSX, JPEG, MP4, etc.). Security and privacy controls are intentionally out of scope and are left to implementers.
Key Topics
- Hierarchical file structure: A multi‑level folder tree that shards patient identifiers (first 3 chars, 4–6 chars, full ID) to improve search and balance folder sizes.
- Directory naming rules: Rules for building consistent folder names (root → patient ID segments → transaction date → contents description) to enable predictable file placement and retrieval.
- Required metadata: Metadata derived from HL7 V2.5 or document headers used to populate folders and filenames, including:
- Patient ID (padded to ≥6 characters when necessary)
- Transaction date/time (ISO 8601 basic format YYYYMMDD or YYYYMMDDhhmmssfff)
- Contents description (HL7 message type or implementation-specific classification)
- Order number, department code, and a condition flag (valid/invalid)
- HL7 message and document file rules: Separate configuration guidance for HL7 message files and generic document files to ensure consistency across transaction types.
- Implementation guidance: Recommends an implementation guide for operational details (including timezone standardization such as UTC) while leaving privacy/security to local policy.
Applications
ISO/TS 24289:2021 is designed for practical, low‑cost secondary storage scenarios:
- Shared clinical data pools and regional exchange where a simple folder-based archive is preferred
- EMR backup, document archive, and disaster-recovery storage
- Clinical research repositories that ingest transaction extracts instead of primary records
- Hospital IT, EHR vendors, health information exchanges, and systems integrators seeking an interoperable, file-system-based storage layout
Benefits include reduced operational complexity (no DB engine required), vendor neutrality, and ease of adoption.
Related Standards
- ISO/HL7 27931:2009 (HL7 Version 2.5) - referenced as the primary message format supported
- Prepared by ISO/TC 215 (Health informatics)
Keywords: ISO/TS 24289:2021, hierarchical file structure, health informatics, HL7 Ver2.5, secondary storage, clinical data archive, directory naming, metadata, patient ID, transaction date.