Dose syntax implementation guidance for FHIR STU3

This guidance is under active development by NHS Digital and content may be added or updated on a regular basis.
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Code Systems

Units of Measure

A unit of measure is required when describing a dosage and can be supplied via one of the following:

The Unified Code for Units of Measure (UCUM)

The Unified Code for Units of Measure (UCUM) is preferred and should be used where possible.

Examples of when a UCUM unit of measure would be used are:

  • gram (g)
  • milliliter (ml)
  • percent (%)

SNOMED

In the instance where a UCUM unit of measure is not defined, use a SNOMED-CT unit of measure instead. All units of measure are descendants of concept 767524001 | Unit of measure (qualifier value) which includes both UCUM and non-UCUM codes.

Concept 732935002 | Unit of presentation (unit of presentation), which is also a descendant of the Unit of measure concept, holds a list non-UCUM units of measure that are used within prescribing:

Examples of where a SNOMED-CT unit of measure would typically be used are:

  • tablet
  • capsule
  • ampoule
  • patch
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