CCDA to FHIR

Introduction¶

The ccda-to-fhir transformation library is designed to convert clinical documents structured in the Consolidated Clinical Document Architecture (C-CDA) format into FHIR format. This library provides utilities to map and transform C-CDA elements, such as patient information, medical history, and treatment records, into corresponding FHIR resources, ensuring seamless integration and utilization of healthcare data across modern healthcare systems. The transformation process adheres to established standards, promoting interoperability and data consistency within healthcare applications.

This library provides a streamlined and efficient way for developers to convert CCD-A documents into the FHIR R4 format, enabling seamless integration with FHIR-based healthcare systems.

Mapping C-CDA Patient to FHIR r4¶

The body of a C-CDA document contains the clinical content, which is organized into structured sections. Each section corresponds to different types of clinical information, such as Patient information, Immunizations, Medications, Allergies, Problems, Procedures. Each section in the body is represented as an XML element with a specific structure, typically including a title, code (for standardized representation), and entries. Entries are sub-elements that provide detailed information, such as specific medications or results.

Note

WSO2 Healthcare Solution offers two distinct solutions (Ballerina and Micro Integrator) each tailored to different architectural preferences. For systems that favor the Enterprise Service Bus (ESB) pattern, the Micro Integrator, enhanced with FHIR accelerators, can be utilized.
On the other hand, Ballerina, a programming language specifically designed for integrations, is ideal for implementing FHIR integrations structured as microservices.

Ballerina

To create a new ballerina project, execute the following command.
```
bal new v2toFHIR
```

Now our Ballerina project has been created. We are now going to transform the following C-CDA message.

<?xml version="1.0" encoding="UTF-8"?>
<ClinicalDocument xmlns="urn:hl7-org:v3" xmlns:voc="urn:hl7-org:v3/voc">
  <realmCode code="US"/>
  <typeId root="2.16.840.1.113883.1.3" extension="POCD_HD000040"/>
  <templateId root="2.16.840.1.113883.10.20.22.1.1"/>
  <id root="2.16.840.1.113883.19.5.99999.1" extension="123456789"/>
  <code code="18842-5" codeSystem="2.16.840.1.113883.6.1" codeSystemName="LOINC" displayName="Discharge summary"/>
  <title>Continuity of Care Document</title>
  <effectiveTime value="2023-05-21T08:00:00"/>
  <confidentialityCode code="N" codeSystem="2.16.840.1.113883.5.25" displayName="Normal"/>
  <languageCode code="en-US"/>
  <recordTarget>
    <patientRole>
      <id extension="123-45-6789" root="2.16.840.1.113883.4.1"/>
      <addr use="HP">
        <streetAddressLine>123 Main Street</streetAddressLine>
        <city>Anytown</city>
        <state>NY</state>
        <postalCode>12345</postalCode>
      </addr>
      <patient>
        <name use="L">
          <given>John</given>
          <family>Doe</family>
          <prefix>Mr</prefix>
          <suffix>PhD</suffix>
        </name>
        <administrativeGenderCode code="UN" displayName="Other"/>
        <birthTime>20230531</birthTime>
      </patient>
    </patientRole>
  </recordTarget>
  <!-- Additional sections with clinical information would follow here -->
</ClinicalDocument>

To understand what each field contains in the above message, you can refer to the C-CDA spec for the mappings.

To convert the above hl7v2.3 message to FHIR resource format, add the following code to the main.bal file.

import ballerina/io;
import ballerinax/health.fhir.r4;
import ballerinax/health.fhir.r4utils.ccdatofhir;

xml ccdaMsg = xml `<?xml version="1.0" encoding="UTF-8"?>
<ClinicalDocument xmlns="urn:hl7-org:v3" xmlns:voc="urn:hl7-org:v3/voc">
  <realmCode code="US"/>
  <typeId root="2.16.840.1.113883.1.3" extension="POCD_HD000040"/>
  <templateId root="2.16.840.1.113883.10.20.22.1.1"/>
  <id root="2.16.840.1.113883.19.5.99999.1" extension="123456789"/>
  <code code="18842-5" codeSystem="2.16.840.1.113883.6.1" codeSystemName="LOINC" displayName="Discharge summary"/>
  <title>Continuity of Care Document</title>
  <effectiveTime value="2023-05-21T08:00:00"/>
  <confidentialityCode code="N" codeSystem="2.16.840.1.113883.5.25" displayName="Normal"/>
  <languageCode code="en-US"/>
  <recordTarget>
    <patientRole>
      <id extension="123-45-6789" root="2.16.840.1.113883.4.1"/>
      <addr use="HP">
        <streetAddressLine>123 Main Street</streetAddressLine>
        <city>Anytown</city>
        <state>NY</state>
        <postalCode>12345</postalCode>
      </addr>
      <patient>
        <name use="L">
          <given>John</given>
          <family>Doe</family>
          <prefix>Mr</prefix>
          <suffix>PhD</suffix>
        </name>
        <administrativeGenderCode code="UN" displayName="Other"/>
        <birthTime>20230531</birthTime>
      </patient>
    </patientRole>
  </recordTarget>
  <!-- Additional sections with clinical information would follow here -->
</ClinicalDocument>`;

function convertCcdaToFhir() returns json|error{
    r4:Bundle|r4:FHIRError ccdatofhirResult = ccdatofhir:ccdaToFhir(ccdaMsg);
    io:println("Transformed FHIR message: ", (check ccdatofhirResult).toString());
}

public function main() returns error?{
        _= check convertCcdaToFhir();
}

Run the Ballerina code using bal run command. You will get the following FHIR bundle as the response.

{
    "resourceType": "Bundle",
    "meta": {
        "profile": [
            "http://hl7.org/fhir/StructureDefinition/Bundle"
        ]
    },
    "type": "searchset",
    "entry": [
        {
            "resource": {
                "resourceType": "Patient",
                "gender": "other",
                "telecom": [],
                "identifier": [
                    {
                        "system": "http://hl7.org/fhir/sid/us-ssn",
                        "value": "123-45-6789"
                    }
                ],
                "address": [
                    {
                        "use": "home",
                        "line": [
                            "123 Main Street"
                        ],
                        "city": "Anytown",
                        "state": "NY",
                        "postalCode": "12345"
                    }
                ],
                "managingOrganization": {
                    "display": ""
                },
                "name": [
                    {
                        "family": "Doe",
                        "given": [
                            "John"
                        ],
                        "prefix": [
                            "Mr"
                        ],
                        "suffix": [
                            "PhD"
                        ]
                    }
                ]
            }
        }
    ]
}

Using Pre-built Services¶

This service can be used to transform C-CDA messages into FHIR resources.

You can clone the open-healthcare-prebuilt-services repository and start the ccda-to-fhirr4-service.
```
bal run
```

Invoke the API as below.

curl --location 'http://localhost:9090/transform' \
--header 'Content-Type: application/xml' \
--data '<?xml version="1.0" encoding="UTF-8"?>
<ClinicalDocument xmlns="urn:hl7-org:v3" xmlns:voc="urn:hl7-org:v3/voc">
  <realmCode code="US"/>
  <typeId root="2.16.840.1.113883.1.3" extension="POCD_HD000040"/>
  <templateId root="2.16.840.1.113883.10.20.22.1.1"/>
  <id root="2.16.840.1.113883.19.5.99999.1" extension="123456789"/>
  <code code="18842-5" codeSystem="2.16.840.1.113883.6.1" codeSystemName="LOINC" displayName="Discharge summary"/>
  <title>Continuity of Care Document</title>
  <effectiveTime value="2023-05-21T08:00:00"/>
  <confidentialityCode code="N" codeSystem="2.16.840.1.113883.5.25" displayName="Normal"/>
  <languageCode code="en-US"/>
  <recordTarget>
    <patientRole>
      <id extension="123-45-6789" root="2.16.840.1.113883.4.1"/>
      <addr use="HP">
        <streetAddressLine>123 Main Street</streetAddressLine>
        <city>Anytown</city>
        <state>NY</state>
        <postalCode>12345</postalCode>
      </addr>
      <patient>
        <name use="L">
          <given>John</given>
          <family>Doe</family>
          <prefix>Mr</prefix>
          <suffix>PhD</suffix>
        </name>
        <administrativeGenderCode code="UN" displayName="Other"/>
        <birthTime>20230531</birthTime>
      </patient>
    </patientRole>
  </recordTarget>
  <!-- Additional sections with clinical information would follow here -->
</ClinicalDocument>'

You should be able to get the same above response.