"A dimensioned quantity expressing the result of measuring" - HL7 V3 "A measured amount (or an amount that can potentially be measured). Note that measured amounts include amounts that are not precisely quantified, including amounts involving arbitrary units and floating currencies." - HL7 FHIR, Quantity. Note that the FHIR Quantity data type includes an optional comparator, which is not commonly used. In FHIM, we have created a sub type (QuantityWithComparator) that adds the comparator property.