HAPI/FHIR
QuantityDt Datatype (A measured or measurable amount)
Definition: 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
Requirements: Need to able to capture all sorts of measured values, even if the measured value are not precisely quantified. Values include exact measures such as 3.51g, customary units such as 3 tablets, and currencies such as $100.32USD