This safe medical practice…

This safe medical practice as defined in the context of prescribing. Not reporting of numeric results, so the objection is not relevant. 

The "^" value could be a problem. It's in V2 but it's not the only way to represent powers. Will ask the UCUM committee to address V3 CDA and FHIR so there aren't delimiters to conflict with.

UCUM should be considered the code in triumvirate of code display text and code system. Senders are free to deliver whatever display text they now send.

Point out industry standards. The problem in observation messages is that they are totally understandardized. 

Strongly support UCUM use so…

Strongly support UCUM use so results can be accurately analyzed.

We strongly concur with the…

We strongly concur with the listing of UCUM here. Daniel Vreeman has compiled a list of UCUM conversion and validation resources here. It is worth noting that UCUM is designed for accomplishing a computable units representation in electronic communication. This is the main interoperability need. Having display strings for humans (whether patients, providers, or others) is another matter. We recommend that the last bullet point (Numerical representation are uniform…) be removed as it totally unclear.

Table 3: Dimensionless units…

Table 3: Dimensionless units. The units ppb and ppt are deprecated because the names “billion” and “trillion” are ambiguous. The expression “10*-9” or “10*-12” should be used instead. When the units percent or “parts per N” are used for concentrations specific units are prefered, e.g., “ug/l” for mass concentration. The expression “ug/kg” for ppb is also valid.
the number ten for arbitrary powers  10n  10*  10*  no 10  1 
the number ten for arbitrary powers  10n  10^  10^  no 10  1 


Both * and ^ can be used for arbitrary powers as shown in the table above (see

Recognize a value set that uses the ^ form.

WHICH values in HL7 conflict? I know SOME values are different, but I have seen none that conflic. See



Good point. Will explore…

Good point. Will explore with users.

Test tool

UCUM validators exist. Ability to test if unit is valid or unit1 converts to unit2 are all valid test tasks. Consider changing n/a in testing to linking to validation and conversion tools.




Thank you for this comment…

Thank you for this comment. Links to these test tools have been added.