Hi Sam
I've discussed this particular case at HL7 before, but I don't
remember whether any answer was agreed. But to me, this case
needs to be coded - there's a fairly small set of reasons why
the laboratory would report that an answer was not available,
and the reasons themselves may have meaning
I advance this small hierarchical vocab:
+ NS - not suitable
+ HM - haemolysed
+ HM1
+ HM2 { rating for how haemolysed
+ HM3 { ? maybe a seperate element
+ HM4
+ LP - lipeamic
+ LP1
+ LP2 { rating for how lipaemic
+ LP3 { ? maybe a seperate element
+ LP4
+ WP - wrong preservative
+ INS - insufficient sample
+ ERR - handling error
+ AGE - too long to deliver to lab or other delivery problem
+ LACC - laboratory accident
+ FAIL - specimen could not be analysed for
technical reasons that were not accidental
I may have missed some heam and micro specific reasons - I
worked in the core lab.
Some Australian laboratories are reporting meaningless
numbers and then reporting the error as a comment, rather
than reporting a null value - so they can be paid. In spite
of my strong clinical objection to this practice, this
suggests that this isn't a null-flavour issue, and indeed,
for lipaemic samples, except for a few analytes, I used to
report the numbers and just note that the numbers were
lower because of the volume effects.
So I think that this is a "laboratory quality indicator"
that is a separate element to the actual value, since
there is various cases where you'd want to report both - and
I think this is worth modelling in the base pathology result
archetype.
Grahame
Sam Heard wrote:
> Dear All
>
> A reminder on why flavour of null is at the ELEMENT level: it allows a
> composition with mandatory data to be saved even if the data is not
> available, or allows a reason to be stated for data that is missing. It
> also allows us to deal with the HL7 flavour of null on the data types.
>
> I am concerned that the flavour of null is set to DV_CODED_TEXT and not
> DV_TEXT (ie. it has to be coded from a terminology). I agree that some
> systems will want things coded for safety in some situations, but I
> believe that this should be handled through archetypes and templates.
>
> Laboratories will want to use this for all sorts of reasons, one clear
> example is when an electrolyte sample has haemolysed - and they cannot
> give a potassium reading (they do not want to omit it!)
>
> So I want to propose that the flavour of null is set to DV_TEXT.
>
> Cheers
> Sam Heard
> -
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