Hi Thomas, In the UK (and ? Aus/NZ), we would not use arbitrary units in UCUM for dose units because the latter are expressed as SNOMED terms, and are used in conjunction with the SNOMED-based dm+d (or AMT) drug dictionary to compute actual doses/amounts where possible.
e.g. 318421004 | Atenolol 100mg tablets | via dm+d allows us to infer that 1 tab (in this case) = 100mg http://dmd.medicines.org.uk/DesktopDefault.aspx?VMP=318421004&toc=nofloat and allows us to do maximum daily dose calculation, at least against a defined subset of such 'dose units'. in other cases the dose unit strength will be defined as part of the medication order - we have a 'Strength' element in the medication order archetype for just such a purpose. I don't think we need to be able to define the unit strength as part of the quantity datatype. Ian Dr Ian McNicoll mobile +44 (0)775 209 7859 office +44 (0)1536 414994 skype: ianmcnicoll email: i...@freshehr.com twitter: @ianmcnicoll Co-Chair, openEHR Foundation ian.mcnic...@openehr.org Director, freshEHR Clinical Informatics Ltd. Director, HANDIHealth CIC Hon. Senior Research Associate, CHIME, UCL On 19 May 2016 at 08:24, Thomas Beale <thomas.be...@openehr.org> wrote: > Hi Gerard, > > they actually could be, but whenever this discussion comes up, no-one > proposes it. I'm not sure if I would either, because these arbitrary units > are still not computable in general, but 'dose units' can be made > computable but only with some extra data fields, i.e. you need both the > quantity of dose in 1 tablet/capsule etc, and also number of tablet/capsule > etc. So the structural model is different anyway. > > I think the other problem with using UCUM arbitrary units is that people / > orgs want to control the names of medicinal delivery products ('tablet' > etc) in a terminology, which is reasonable, but doesn't fit so well with > UCUM. > > - thomas > > On 19/05/2016 08:11, "Gerard Freriks (privé)" wrote: > > Thomas, > > All are Units of a different kind. > > SI defines: Units of Measure, and Units of Quantity in the scientific > domain. > > There are also Units of Time: minute, hour, etc. > > When I think of tablets, capsule, etc. we will call these Units of > Medicinal Product Dose. > Isn’t in UCUM this an example of Arbitrary Units? > 3.2 ARBITRARY UNITS > > *§24 arbitrary units* * ■1* Arbitrary or procedure defined units are > units whose meaning entirely depends on the measurement procedure (assay). > These units have no general meaning in relation with any other unit in the > SI. Therefore those arbitrary semantic entities are called *arbitrary > units*, as opposed to *proper units*. The set of arbitrary units is > denoted *A*, where *A*∩ *U* = {}. * ■2* An arbitrary unit has no further > definition in the semantic framework of *The Unified Code for Units of > Measure* * ■3* Arbitrary units are not “of any specific dimension” and > are not “commensurable with” any other unit. > > Until version 1.6 *The Unified Code for Units of Measure* has dealt with > arbitrary units as dimensionless, but as an effect the semantics of *The > Unified Code for Units of Measure* made all arbitrary units > commensurable. Since version 1.7 of *The Unified Code for Units of > Measure* it is no longer possible to convert or compare arbitrary units > with any other arbitrary unit. > > *§25 operations on arbitrary units* * ■1* Any term involving > arbitrary units, is itself an arbitrary unit and is not comparable with any > other arbitrary unit or term. > > *§26 definition of arbitrary units* * ■1* Arbitrary units are marked > in the definition tables for unit atoms by a bullet (‘•’) in the column > titled “value” and a bullet in the column titled “definition”. > > > Gerard Freriks > +31 620347088 > <gf...@luna.nl>gf...@luna.nl > > > > _______________________________________________ > openEHR-technical mailing list > openEHR-technical@lists.openehr.org > > http://lists.openehr.org/mailman/listinfo/openehr-technical_lists.openehr.org >
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