Saving tresholds in archetypes

Thomas Beale thomas.beale at
Wed Nov 14 08:36:10 EST 2012

HI Kevin,

Normally such thresholds are regarded as 'reference information' or 
'knowledge' that would be available somewhere else in the environment. 
Archetypes enable you to set limits on all kinds of values, but the 
limits are usually regarded as 'sanity' limits.

Using 'rules' in archetypes you could state limits dependent upon 
patient type, age etc, this is more complicated obviously. It will be 
technically doable in ADL 1.5, but I suspect it is not the right 
approach, because you would not want to hide (or replicate) these 
knowledge statements inside archetypes as fixed / static statements.

Better would be a system where limits on values could be stated to be a 
query that takes patient parameters and obtains the information from an 
external reference source. We don't do that kind of thing currently with 
archetypes, and I am not even sure that there would be agreement on this 
idea. The current way of solving the problem is at a higher application 
layer, where data entry is mediated by a connection to the relevant 
knowledge service (e.g. clinical protocols, etc).

ANother thing to note: the DV_QUANTIFIED data types in openEHR have 
normal and other reference ranges in them, which are used to enable lab 
systems to return the ranges that actually apply to that patient. This 
means that an analyte value could be returned with a 'normal' range, an 
'alert' range and a 'critical' range. As far as I know, only normal 
ranges are in routine use.

- thomas

On 14/11/2012 13:01, Kevin Keene wrote:
> Hi all,
> I am rather new to OpenEHR and archetypes. Most of the concept is
> clear to me, but I have a small question at this moment.
> We have to deal with parameters that have tresholds( for
> decision-support). Those threshold-parameters can differ per patient.
> I came to the following construct.
> Is it a good solution to create a COMPOSITION-archetype, with in that 
> two slots
> - An OBSERVATION-archetype containing the definition for the 
> measurement-results
> - An EVALUATION-archetype which contains
> --- the diagnoses/conclusion which can be derived from the comparison
> with the thresholds-parameters.
> --- the thresholds (which can differ per patient) to which the
> measurement-results are compared with
> Or should I store the thresholds via another archetype in a separate
> Or are there more valid solutions?
> Thanks in advance for suggestions.
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