Setting thresholds

GF gfrer at
Wed Feb 28 09:35:26 EST 2018

Gerard   Freriks
+31 620347088
  gfrer at

Kattensingel  20
2801 CA Gouda
the Netherlands

> On 28 Feb 2018, at 14:42, Seref Arikan <serefarikan at> wrote:
> Hi Tom, 
> The original question is talking about 'threshold's changing in time. Would not using reference ranges may make things complicated during implementation with the changing threshold requirement? 

Not when the complete context/epistemology- and thus the actual range-  is stored next to the data value.
What is the complexity?

> First: if the threshold is changing with respect to all instances of a particular composition (template_id = 'x') , when the change happens, would not you have to update reference ranges of the DV_QUANTITY node in all composition instances across all EHRs to express the new threshold? That is, if you define high systolic blood pressure using a reference value, would not you have to update all blood pressure observations when the accepted 'high' value (threshold) changes? 
> Second: Setting the reference value to express a threshold would make it impossible to query above/below threshold sets of composition via AQL because it'd require a query that uses the WHERE clause as follows:
> ".... WHERE some/path/node1.value > /some/path/node1.reference_range.value" (excuse the mock paths) which, as far as I know is not supported by AQL at the moment, not even grammar-wise (I may be out of date on this one) 
> If you keep the reference value at the application level, all you have to do is update it without having to touch the existing instances and use AQL to select above/below threshold since you can plug the threshold value directly into WHER

Leaving epistemological information in the application is. creating problems because ranges change overtime and are true in one geo- and temporal context only.

> You'd have to 

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