FHIR Chat · Questionnaire population for a choice/code

Stream: questionnaire

Topic: Questionnaire population for a choice/code

Corey Wen (Jun 02 2021 at 17:02):

I am trying to prepopulate a questionnaire using fhirpath expression to convert a string to a code, specifically populating a patient's gender.
In the example on "https://lhcforms.nlm.nih.gov/lforms-fhir-app/" for "US Surgeon General family health portrait [54127-6]" the resource Questionnaire has an initialExpression for Gender that uses %patient.gender, but this does not populate the questionnaire.
I found this post "https://chat.fhir.org/#narrow/stream/179266-fhirpath/topic/data.20extraction.20for.20Questionnaires" which is relevant but I was not able to find what was being discussed in the post in "http://hl7.org/fhirpath/" or "https://www.hl7.org/fhir/fhirpath.html"
I found %terminologies.subsumes(system, coded1, coded2, params) : code but wasn't sure if that could be used for this purpose.
How can I populate the questionnaire for choice types?

Lloyd McKenzie (Jun 02 2021 at 17:26):

@Paul Lynch

Paul Lynch (Jun 02 2021 at 18:09):

Until FHIR#29324 is addressed, there isn't a way to create a Coding. However, if you have a Coding somewhere in the Questionnaire, you can use iif statements to pick the Coding you want and assign it via initialExpression.

Paul Lynch (Jun 02 2021 at 18:17):

Example (with calculatedExpression setting a choice item): https://lforms-fhir.nlm.nih.gov/baseR4/Questionnaire/88121-9-x?_format=json

Corey Wen (Jun 03 2021 at 20:55):

I tried following the example but wasn't able to get very far. I read the snippet about iif but still am not sure if I'm following the syntax correctly.
I have the following under the extension for the choice for gender.

        {
            "type": "choice",
            "code": [
                {
                    "code": "LL3324-2",
                    "display": "Sex assigned at birth",
                    "system": "http://loinc.org"
                }
            ],
            "extension": [
                {
                    "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-itemControl",
                    "valueCodeableConcept": {
                        "coding": [
                            {
                                "system": "http://hl7.org/fhir/questionnaire-item-control",
                                "code": "drop-down",
                                "display": "Drop down"
                            }
                        ],
                        "text": "Drop down"
                    }
                },
                {
                    "url": "http://hl7.org/fhir/StructureDefinition/variable",
                    "valueExpression": {
                        "name": "thisItem",
                        "language": "text/fhirpath",
                        "expression": "%questionnaire.item.where(linkId = '/LL3324-2')"
                    }
                },
                {
                    "url": "http://hl7.org/fhir/StructureDefinition/variable",
                    "valueExpression": {
                        "name": "maleCoding",
                        "language": "text/fhirpath",
                        "expression": "%thisItem.answerOption.valueCoding.where(code='LA2-8')"
                    }
                },
                {
                    "url": "http://hl7.org/fhir/StructureDefinition/variable",
                    "valueExpression": {
                        "name": "femaleCoding",
                        "language": "text/fhirpath",
                        "expression": "%thisItem.answerOption.valueCoding.where(code='LA3-6')"
                    }
                },
                {
                    "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-calculatedExpression",
                    "valueExpression": {
                        "description": "Birthsex from patient resource",
                        "language": "text/fhirpath",
                        "expression": "iif(%patient.gender='male', %maleCoding, %femaleCoding)"
                    }
                }
            ],
            "required": false,
            "linkId": "/LL3324-2",
            "text": "Sex assigned at birth",
            "answerOption": [
                {
                    "valueCoding": {
                        "code": "LA2-8",
                        "display": "Male"
                    }
                },
                {
                    "valueCoding": {
                        "code": "LA3-6",
                        "display": "Female"
                    }
                },
                {
                    "valueCoding": {
                        "code": "LA4489-6",
                        "display": "Unknown"
                    }
                }
            ]
        },

Paul Lynch (Jun 03 2021 at 23:44):

That looks good, as far as I can see. Do you have "patient" defined from a launchContext extension somewhere?

Corey Wen (Jun 04 2021 at 14:26):

Yes, I have the following, however the field for gender is not being prepopulated and there are no error messages.

Is the syntax for the comparison "$patient.gender = 'male' and the syntax for the iif correct?
iif(%patient.gender='male', %maleCoding, %femaleCoding)

Also, is there a way to hardcode a initialExpression for a choice type? It may give me more insight.

launchContext for Patient under extension

        {
            "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-launchContext",
            "extension": [
                {
                    "url": "name",
                    "valueId": "patient"
                },
                {
                    "url": "type",
                    "valueCode": "Patient"
                },
                {
                    "url": "descripton",
                    "valueString": "For filling in patient information as the subject for the form"
                }
            ]
        }

Last updated: Apr 12 2022 at 19:14 UTC

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FHIR Chat · Questionnaire population for a choice/code · questionnaire