Others titles

  • FHIR Ratio Datatype
  • Electronic Health Records Exchange Through FHIR


  • FHIR
  • HL7
  • Medical Terminology
  • Processes Data
  • Processes Information
  • Processes Documentation
  • Health Information Exchange
  • Electronic Health Records
  • FHIR Smart
  • Smart on FHIR


A relationship between two Quantity values expressed as a numerator and a denominator. A proper ratio has both a numerator and a denominator; however, these are not mandatory in order to allow an invalid ratio with an extension with further information.

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The Ratio datatype should only be used to express a relationship of two numbers if the relationship cannot be suitably expressed using a Quantity and a common unit. Where the denominator value is known to be fixed to “1”, Quantity should be used instead of Ratio. Numerator and denominator Shall both be present, or both are absent. If both are absent, there shall be some extension present.

It includes examples where a Quantity is typically used are rates, densities, concentrations. Examples where a Ratio is used are: titers (e.g. 1:128); concentration ratios where the denominator is significant (e.g. 5mg/10mL); observed frequencies (e.g. 2 repetitions/8 hr), and where the numerator or denominator is an amount of a currency (no Unified Code for Units of Measure (UCUM) code for $ etc.). Common factors in the numerator and denominator are not automatically cancelled out. Ratios are not simply “structured numbers” – for example, blood pressure measurements (e.g. “120/60”) are not ratios.

In Ratio.extension, extensions are the additional content defined by impleentations and are always sliced by (at least) url. It may be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that shall be met as part of the definition of the extension. There can be no stigma associated with the use of extensions by any application, project, or standard – regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the Fast Healthcare Interoperability Resources (FHIR) specification to retain a core level of simplicity for everyone.

Ratio is used in the following places:
– Dosage
– Goal
– Medication
– MedicationAdministration
– MedicationKnowledge
– MedicinalProductIngredient
– MedicinalProductPharmaceutical
– NutritionOrder
– Observation
– ServiceRequest
– Substance
– SubstanceSpecification

About this Dataset

Data Info

Date Created


Last Modified




Update Frequency


Temporal Coverage


Spatial Coverage

United States


John Snow Labs; Health Level Seven International;

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FHIR, HL7, Medical Terminology, Processes Data, Processes Information, Processes Documentation, Health Information Exchange, Electronic Health Records, FHIR Smart, Smart on FHIR

Other Titles

FHIR Ratio Datatype, Electronic Health Records Exchange Through FHIR

Data Fields

Name Description Type Constraints
Concept_NameName of the concept in the FHIR structurestringrequired : 1
Computer_Ready_NameA Computer-ready name (e.g. a token) that identifies the structure - suitable for code generation. Note that this name (and other names relevant for code generation, including element & slice names, codes etc) may collide with reserved words in the relevant target language, and code generators will need to handle this.string-
TypeThe type the structure describes.string-
Dollar_RefThe "$ref" string value contains a Uniform Resource Identifier (URI) which identifies the location of the JSON value being referenced.string-
DescriptionA free text natural language description of the structure and its use.string-
ItemsThe value of the keyword should be an object or an array of objects. If the keyword value is an object, then for the data array to be valid each item of the array should be valid according to the schema in this value.string-

Data Preview

Concept NameComputer Ready NameTypeDollar RefDescriptionItems
Ratioid#/definitions/stringUnique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.
RatioextensionarrayMay be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable
Rationumerator#/definitions/QuantityThe value of the numerator.
Ratiodenominator#/definitions/QuantityThe value of the denominator.