robeastwood-agency / fhir-mapping-experiments

Goal

Transform FHIR Coverage instances - from version 1.4 to R4 using:

• instance of v1.4 Coverage
• FHIR mapping language - see coveragev14toR4.map
• transform operation on Matchbox server - see test http file

Assumptions

• no 'out of the box' support for FHIR 1.4, therefore in an attempt to circumvent this, the respective StructureDefinitions were obtained and used (note- not sure if this approach is valid/workable, but we are giving it a try)

What we have done

1. Coverage v1.4 StructureDefinition

   • downloaded from the FHIR spec here https://hl7.org/fhir/2016May/coverage.profile.xml.html
   • updated the following elements to identify and differentiate as v1.4
     • StructureDefinition.id to Coveragev14
     • StructureDefinition.url to http://example.org/fhir/StructureDefinition/Coveragev14
     • StructureDefinition.name to Coveragev14
   • saved here: StructureDefinition-coverage-v14.xml
   • POSTed to matchbox using this REST request

2. Coverage R4 StructureDefinition

   • downloaded from the FHIR spec here https://hl7.org/fhir/R4/coverage.profile.xml.html
   • updated the following elements to identify and differentiate as R4
     • StructureDefinition.id to CoverageR4
     • StructureDefinition.url to http://example.org/fhir/StructureDefinition/CoverageR4
     • StructureDefinition.name to CoverageR4
   • saved here: StructureDefinition-coverage-R4.xml
   • POSTed to matchbox using this REST request

3. FML map file

   • created FML file: coveragev14toR4.map
   • Added the above 2 URLs into the map file as source and target (see here)
   • added FML rules to transform various v1.4 elements to respective R4 elements

4. v1.4 example Coverage instance

   • an example from the v1.4 FHIR specification was downloaded to use as the input to the transform
   • saved here
   • a couple of optional elements not present were added in order to invoke the respective rule (ie network and contract)

5. Transform operation

   • issued the transform operation with this REST request

6. Transform result

   • an instance of Coverage is successfully generated, however there are some gaps - see below

Transformed output

<?xml version="1.0" encoding="UTF-8"?>
<Coverage xmlns="http://hl7.org/fhir">
  <identifier>
    <system value="http://benefitsinc.com/certificate"/>
    <value value="12345"/>
  </identifier>
  <dependent value="1"/>
  <period>
    <start value="2014-05-23"/>
    <end value="2012-05-23"/>
  </period>
  <network value="test"/>
  <contract>
    <reference value="Contract/4"/>
    <display value="Contract no 4"/>
  </contract>
</Coverage>

Transform gaps

1. Coverage.issuerReference -> Coverage.payor

   • v1.4 Coverage.issuerReference is member of choice group Coverage.issuer and is of datatype Reference
   • R4 Coverage.payor is of datatype Reference
   • a number of rule variations have not yet yielded a successful transform
   • note that a transform of Coverage.contract -> Coverage.contract (also datatype Reference) does yield success

2. Coverage.beneficiaryReference -> Coverage.beneficiary

   • as datatype Reference - same issue as above

3. Datatype transform Coding to CodeableConcept

   • cannot figure out how to transform these elements:
     • Coverage.type (Coding) -> Coverage.type (CodeableConcept)
     • Coverage.relationship (Coding) -> Coverage.relationship (CodeableConcept)
   • see rule attempt here