FHIR Chat · Modifier Extensions

Stream: implementers

Topic: Modifier Extensions

Patricia Alves (Apr 29 2016 at 09:40):

Hi, is it possible to add a modifier extension to a "date" element? Thank you

Grahame Grieve (Apr 29 2016 at 09:41):

no. it's not possible. What's your use case?

Patricia Alves (Apr 29 2016 at 09:53):

In the case of Immunization.wasNotGiven = true, in the Immunization.date I set the date when the non-immunization was registered, but I also need to set a period (with begin and if aplicable, end) for the non-immunization event, since the non-immunization has a start and may have an end

Grahame Grieve (Apr 29 2016 at 09:55):

it doesn't sound like a modifier to me. if you didn't understand the extension, it wouldn't change the fact that the immunization record is an assertion of was-not-given made on a given date

Grahame Grieve (Apr 29 2016 at 09:55):

further, it's an extension on the statement, not on the date of the statement

Grahame Grieve (Apr 29 2016 at 09:55):

that's what I think anyway

Patricia Alves (Apr 29 2016 at 09:55):

So, I created a modifierExtension for that, and I thought it could be inserted in the date element. Here is the extension:
"modifierExtension" : [
{
"url" : "Vacinas/NoVaccinationBeginDate",
"valueDate" : "2016-02-19"
},
{
"url" : "Vacinas/NoVaccinationEndDate",
"valueDate" : "2016-03-20"
}
],

Patricia Alves (Apr 29 2016 at 09:57):

So you are saying it should be an Extension instead of a modifier? and that I should place it at the base of the Immunization resource?

Grahame Grieve (Apr 29 2016 at 09:57):

yes to both.

Patricia Alves (Apr 29 2016 at 09:57):

thanks a lot :)

Grahame Grieve (Apr 29 2016 at 09:58):

no problems. btw, the extension URLs both need to be absolute URLs that point to the extension definitions.

Grahame Grieve (Apr 29 2016 at 09:58):

and you could also use a period:

Patricia Alves (Apr 29 2016 at 10:00):

ah ok, the specification says the url is of type uri, so I thought this "Vacinas/NoVaccinationBeginDate" would be valid

Grahame Grieve (Apr 29 2016 at 10:00):

"extension" : [  {
  "url" : "http://patricias.server/extensions/NoVaccination",  
  "valuePeriod" :  { 
    "begin " :  "2016-02-19",
   "end" : "2016-03-20"
  }
}],

Patricia Alves (Apr 29 2016 at 10:01):

yeah that's better, i'll use the period :) thx

Grahame Grieve (Apr 29 2016 at 10:01):

yes, but it also says: The url is a mandatory attribute / property and identifies a retrievable extension definition that defines the content and meaning of the extension

Grahame Grieve (Apr 29 2016 at 10:02):

we could probably be clearer there - it needs to be retrievable, so that a system can fetch the definition of the extension, and use the data (e.g. know how to present it to a user)