I’m not going to town on the why you would use it but some good reasons are here questionnaire | Hay on FHIR David Hay discusses many simple use cases.
The example I will use is the End Of Life Care API from NHSEngland/NHSDigital/Yorkshire Ambulance Service.
This uses version 1.2 of this specification Introduction to FHIR End of Life API | FHIR-END-OF-LIFE-API
The SCCI 1580 has been turned into a FHIR Questionnaire and a set of profiles on FHIR resources. The Questionnaire can be found on this link: FHIR Explorer
(or by using postman GET https://data.developer.nhs.uk/ccri-fhir/STU3/Questionnaire/4)
This Questionnaire defines how the FHIR QuestionnaireResponse should be built. So it doesn’t define how the form will look, it just defines how the system returns the information.
An example QuestionnaireResponse conforming to these rules can be found by running this query
If you run this query you can also validate it conforms to the questionnaire by using the validation service in the CCRI (FHIR Explorer). If you try this you should find one issue (that’s a fault in the CCRI)
[Note: the Questionnaire to validate against must be on the CCRI, the CCRI supports POST Questionnaire so you can add your own]
A rendered version of the EOLC QuestionnaireResponse can be found on the HIE Portal. First search for Patient ‘Kewn’ and when the summary record is displayed click on the EOLC button
The EOLC screen is designed to look like a clinical system, the layout matches the Questionnaire.
The HIE doesn’t use the query mentioned above instead it asks the server for a response for the EOLC Questionniare (url = https://fhir.nhs.uk/STU3/Questionnaire/CareConnect-EOLC-1) and also asks the server to return all resources referenced by the QuestionaireResponse. This results in the following query:
The additional parameters select the patient and set the size of the result.