GDL rules with "age-dependent" reference ranges

Birger Haarbrandt birger.haarbrandt at
Mon Feb 29 10:58:10 EST 2016

Hi there,

besides of our core acitivities, we recently fiddled a little with GDL 
to evaluate, if it might be of use for a decision support project in the 
context of a pediatric ICU. One challenge with guidelines in pediatric 
patients is that the reference ranges of variables depent on the age of 
a patient at the time of the clinical event.

In SPARQL/SWRL (as in XML) I can easily calculate the number of days 
between the birth of a patient and the clinical event by simply subtract 
the datetime of the event from the datetime of the birth. The result is 
of type "duration".

In the data types information model specs it says:

"For example, two dates can be subtracted, but the result is a duration, 
not another date. For this reason, the operations add, subtract and diff 
are defined rather than ‘+’ or ‘-’. Date/time types, as well as the relative
concept duration, are defined in the Date Time Package on page 54." and

"The DV_DURATION class is used for expressing durations of clinical 
phenomena and differences
between absolute times"

So I expect this to work identically.

If I try this operation using the test function of the GDL Editor, the 
result test set for any example data entry is empty. I made a CDS 
archetype with an element of type Duration to store the result. In GDL 
it looks as follows:

rules = <
             ["gt0025"] = (RULE) <
                 when = <"$gt0024!=null",...>
                 then = 
                 priority = <1>

Is this a bug or did I miss something?

Any help is really appreciated.


*Birger Haarbrandt, M.Sc.*

Peter L. Reichertz Institut für Medizinische Informatik
Technische Universität Braunschweig und
Medizinische Hochschule Hannover
Mühlenpfordtstraße 23
D-38106 Braunschweig

T +49 (0)531 391-2129
F +49 (0)531 391-9502
birger.haarbrandt at

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