This elements is provided to support the Measurement element, which can be used to report a numerical value such as LOINC:26515-7, Platelets [#/volume] in Blood. The normal range for circulating platelets is 150,000 to 450,000 platelets per microliter.

Data model

Field Type Multiplicity Description
unit OntologyClass required Ontology term describing the unit.
low double 1..1 lower range of normal. REQUIRED.
high double 1..1 upper range of normal. REQUIRED.


There are several ontologies that provide terms for units of measurement, including the Units of measurement ontology and the National Cancer Institute Thesaurus (NCIT), from the subhierarchy for Unit of Measure (Code C25709).

The following example shows the reference range for platelet count per microliter.

      id: "UO:0000316"
      label: "cells per microliter"
  low: 150000.0
  high: 450000.0