Overview
ISO 20334:2018 - Traditional Chinese medicine - Coding system of formulae defines a standardized coding system for TCM formulae. The standard specifies rules to encode formulae and provides specific codes for 1,233 frequently-used formulae (1,165 in Annex B and 68 Korean formulae in Annex C). Chinese patent medicines (CPM) and Kampo formulae are explicitly outside the scope. ISO 20334:2018 is intended for use in TCM databases, electronic medical records (EMR), prescriptions and clinical, research and teaching systems.
Key technical topics and requirements
- Coding principles: Uniqueness (each formula has a unique code), scalability (space for expansion) and stability (codes remain unchanged unless formula characteristics change).
- Seven-layer coding structure: The code uses 10 Arabic digits arranged in seven layers that classify and identify each formula by category, action and sequence number.
- Layer 1: category of agriculture/medicine - formulae use “0” (per ISO 18668‑1)
- Layer 2: product code of Chinese medicines - symbolized by “6”
- Layer 3: formula category - symbolized by “0”
- Layer 4: main code (2 digits) - action-based categories (e.g., exterior‑releasing, purgative, harmonizing, heat‑clearing; Sasang constitution codes 41–44)
- Layer 5: subdivided code (1 digit) - secondary classification under main action
- Layer 6: sequence number (3 digits) - ordinal position in code tables
- Layer 7: check digit (1 digit) - calculated according to ISO/IEC 15420 (see Annex A)
- Coding technology: Classification is action-oriented and intended for machine-readable databases and bar-code-compatible implementations (check digit per ISO/IEC 15420).
- Normative annexes: Annex A (check digit calculation), Annex B (codes of formulae), Annex C (Korean formulae codes).
Practical applications and users
ISO 20334:2018 is designed for:
- Hospitals and TCM clinics implementing standardized TCM prescriptions in EMRs and e-prescribing systems
- Clinical informatics and software vendors building medication databases, decision support and interoperability layers
- Researchers and educators maintaining consistent formula references for teaching and scientific studies
- Regulators and quality managers tracing prescriptions and monitoring safe use of formulae
Benefits include improved interoperability, traceability, clearer recordkeeping, and facilitation of international academic exchange of formulae.
Related standards
- ISO/IEC 15420 - Automatic identification and data capture techniques - EAN/UPC bar code symbology (used for check digit calculation)
- ISO 18668‑1:2016 - Traditional Chinese medicine - Coding system for Chinese medicines - Part 1: Coding rules for Chinese medicines (referenced for Layer 1/2 conventions)
Keywords: ISO 20334:2018, TCM formula coding, coding system of formulae, Traditional Chinese Medicine, TCM electronic medical records, formula codes, ISO 18668-1, ISO/IEC 15420.