Pathology requirements UNITS

Technical (archive)
1

UNITS

There are a lot of units out there - it has been our idea to build a
constraint model on units based on the property being measured. A good
example is frequency can be '/{time unit}' (e.g. /min, /hr, /s) or 'Hz'. It
is hoped that we can translate from one to the other as much as possible on
this basis.

It has come to my attention just how many units are out there and that some
units are not translatable to another unit even when the property is the
same without further information. The best known example is gm percent -
which is the same as gm/100ml or gm/dl. This is a concentration but it is
not possible to know the amount of substance (moles) without knowing the
molecular weight of the substance. This means we will have to have units
available in a property that are not translatable. We could separate these
to MASS CONCENTRATION and CONCENTRATION as some have done - but I think
clinicians will want to choose from as small as list as possible.

We need some work done in this area and there are a number of documents
available to get this as tidy as we can.

Cheers, Sam

2

Can we not work on a UNITS module where a test can be attached to a number
of units where the conversion is not available. A clinician does not want to
have to relearn the unit for the convenience of the application.

Bhupinder

3

Bhupinder

This is an interesting idea...but it raises issues as you have to have
normal ranges for each of these. I do not see why the results could not be
duplicated in multiple units is required - at present we do not have the
ability to add multiple values to a single element apart from as reference
ranges.

What do others think? I think Labs will probably push back on this one.

Sam

4

Sam et al,
At least in the Australian context there are regulatory requirements
to report in "Standard" units only. So reporting the same
result in multiple different units is not possible.
What the standard units are, will vary across different realms

Regards
Vince

Dr Vincent McCauley

5

I wonder if units should be considered part of a localsation profile?
Currently you can specify units in an archetype in two ways:

a) as the actual units you want to allow, e.g. units matches {"mm[Hg]"}, units
matches {"km", "mi"}

b) property matches {"pressure"}, property matches {"length"}

A nice alternative that Sam has thought of is:

c) property matches {FORCE/LENGTH^2} -- same as pressure
property matches {LENGTH/TIME}

We are currentl working on including this in ADL.

- thomas

6

Thomas

It is more that units match "Force"/"Length"^2 for pressure and it is an
expression that the property of pressure is the property of "Force" per
property of "area" - this does allow a very wide range of units to be used
if that is the requirement.

I am starting to see that things do get complicated out there in Unitsville.

Cheers, Sam