Stream: implementers
Topic: Multiple Quantity
Jeffy Mathew Jose (Sep 27 2017 at 07:43):
Is there any way to represent multiple quantities of same thing in FHIR?
As an example, my system allows labresults to be stored as string and set of coded values. Each value represents the same data but using different units. As I convert them to Observation, the best place to record them is Observation.Value but it allows only one value
Michel Rutten (Sep 27 2017 at 11:26):
Hi @Jeffy Mathew Jose, maybe you can use Observation.component.value to specify a list of values.
Jeffy Mathew Jose (Sep 27 2017 at 13:33):
@Michel Rutten That seems to do it. But how to differentiate between multiple result of one component vs results of multiple components
Michel Rutten (Sep 27 2017 at 13:37):
Hi @Jeffy Mathew Jose, Alternatively, you could specify the values as SampledData, which allows you to express a series of datapoints as a concatenated, space-delimited string:
https://www.hl7.org/fhir/datatypes-definitions.html#SampledData.data
Jeffy Mathew Jose (Sep 27 2017 at 13:52):
@Michel Rutten SampledData won't help me as units can be different. I am trying to reach a logic based on code for component and root observation code. I shall update after testing few cases
Michel Rutten (Sep 27 2017 at 14:05):
I see the problem. Looks like the Observation resource wasn't designed to hold multiple representations in different units of the same (component) value. Then I guess you'd have to resort to using extensions...?
Yunwei Wang (Sep 27 2017 at 14:22):
@Jeffy Mathew Jose You can use Observation.component.code to distinguish one component vs mutiple components. Multiple data from same component have the same component.code value.
Lloyd McKenzie (Sep 27 2017 at 15:06):
It sounds like you're essentially providing "translations" of the Quantity - 39 inches vs. 1 meter. If so, my leaning would be to define an extension on Quantity for this purpose. And I think it'd be appropriate to submit a change request to have that added to the core specification. The string representation would also be an extension.
Eric Haas (Sep 27 2017 at 15:20):
@Lloyd McKenzie is suggesting core extension right? Although servers can do the conversion for you based on your query.
Eric Haas (Sep 27 2017 at 15:23):
I'm not sure how useful it is to have an extension when LOINC provide codes for various units why not use them + components
Lloyd McKenzie (Sep 27 2017 at 19:09):
Because you won't necessarily only want to do this when you're dealing with Observation.quantity.
Grahame Grieve (Oct 03 2017 at 01:33):
actually, I thought it was here: http://build.fhir.org/iso-21090.html but it's not. So that's where it should be defined
Last updated: Apr 12 2022 at 19:14 UTC
