Fwd: Setting thresholds

Jussara macedo jussara.macedo at gmail.com
Wed Feb 28 09:18:50 EST 2018

I think the functionality seeked here is a threshold to trigger some
action, like an alert. The given example was BP, and as an observation
archetype it only records the blood pressure, using  constraints to set up
only the valid values, which are 0 to maybe up 300.
The ranges are additional information that you can put to help the
clinician’s evaluation, but only rules can make the computer take some
That is what I meant

--------- Mensagem encaminhada ---------
De: Thomas Beale <thomas.beale at openehr.org>
Data: qua, 28 de fev de 2018 às 10:19
Assunto: Re: Setting thresholds
Para: <openehr-technical at lists.openehr.org>, For openEHR clinical
discussions <openehr-clinical at lists.openehr.org>

Although Jussara is right in terms of reference ranges generally, i.e. what
you see in a pathology handbook as ref ranges for male / female / child for
say Total Cholesterol or some other analyte, the openEHR Reference Model
does allow reference ranges to be carried in DV_QUANTITY (see here on the
UML site
DV_ORDERED.normal_range and other_reference_ranges). We do this for the
same reasons Karsten explicates below.

The idea is that the normal range (and other ranges) *specific to the
patient type for the current test order* (sex, age, sometimes 'race', e.g.
African American cholesterol normal range is +10%) can be written into the
data. So, say the patient is a 64 yo female caucasian, and the analyte is
'total cholesterol'. The ref range will be (something like):

   - normal range: 159-276 mg/dL or in SI, 4.12-7.15 mmol/L

that is just one row from a table of normal ranges keyed by sex, age and
with the modifier for African Americans (I have a US path manual, probably
it is just 'African' elsewhere).

The reference range data is often influenced by other factors depending on
what it is, e.g. location, diet, and so on.

The point is, that the path lab can help the doc by including the relevant
normal range with the measured value, and therefore also generate an
'abnormal' indicator in the result. This is a significant time-saver for
doctors, and it also has the effect of writing into the EHR the reference
range that was actually used to decide that the patient was abnormal for
that analyte and to intervene - i.e. it's the reference knowledge for the

- thomas

On 28/02/2018 12:43, Karsten Hilbert wrote:

On Wed, Feb 28, 2018 at 12:18:24PM +0000, Jussara Macedo Rötzsch wrote:

Ranges  aren’t actually part   of the Information model, they are rules for
decision support, and therefore belong to the Application level, like a gdl
based CDS

In practice there are still needs to store ranges (with the data):

1) path labs will attach ranges to recommended interpretations

	those are best stored "with" the result(-interpretation)

	and, no, it is not sufficient to attach them to the test
	*type* of a measurement

2) ranges applied by a clinician upon which a conclusion
   has been made

	those will often end up as textual part of a SOAP note

Think of a patient with warfarin monitoring: The lab will cry
foul (if not properly informed) but the clinician is happy
when the INR is in the therapeutic range.

GNUmed "solves" that by allowing to attach both a "nominal"
and a "desired" range to each test result.

For what that's worth.


Thomas Beale
Principal, Ars Semantica <http://www.arssemantica.com>
Consultant, ABD Team, Intermountain Healthcare
Management Board, Specifications Program Lead, openEHR Foundation
Chartered IT Professional Fellow, BCS, British Computer Society
Health IT blog <http://wolandscat.net/> | Culture blog
openEHR-clinical mailing list
openEHR-clinical at lists.openehr.org
Jussara Rötzsch Sent from Gmail Mobile
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