---
type: "example"
title: "SearchParameter Example: searchparameter-example-extension"
resource: "SearchParameter"
example: "searchparameter-example-extension"
---
# SearchParameter Example: searchparameter-example-extension

## Example XML



```xml
<?xml version="1.0" encoding="UTF-8"?>

<SearchParameter xmlns="http://hl7.org/fhir">
  <id value="example-extension"/>
  <url value="http://hl7.org/fhir/SearchParameter/example-extension"/>
  <name value="ExampleSearchParameterOnAnExtension"/>
  <title value="Example Search Parameter on an extension"/>
  <status value="draft"/>
  <experimental value="true"/>
  <publisher value="HL7 International / FHIR Infrastructure"/>
  <contact>
    <telecom>
      <system value="url"/>
      <value value="http://hl7.org/fhir"/>
    </telecom>
  </contact>
  <description value="Search by url for a participation agreement, which is stored as an extension referencing a DocumentReference"/>
  <code value="part-agree"/>
  <base value="Patient"/>
  <type value="reference"/>
  <expression value="Patient.extension('http://example.org/fhir/StructureDefinition/participation-agreement').value"/>
  <processingMode value="normal"/>
  <target value="DocumentReference"/>
</SearchParameter>
```