# CQL FHIR Query Pattern Coverage - Using CQL With FHIR v3.0.0-ballot

## Extension: CQL FHIR Query Pattern Coverage 

Describes the extent to which the FHIR query patterns given for a data requirement (i.e. the cqf-fhirQueryPattern extensions present on the data requirement) cover the criteria of that data requirement. Because the query patterns for a data requirement are considered as a set (i.e. the union of the results of the query patterns represents the data for the data requirement), coverage is a characteristic of the data requirement as a whole, rather than of any individual query pattern. A coverage of `total` indicates that no further filtering of the results is required; any other value indicates that the consumer must apply the criteria of the data requirement to the results of the query patterns.

**Context of Use**

**Usage info**

**Usages:**

* Use this Extension: [CQL Module](StructureDefinition-cql-module.md)
* Examples for this Extension: [EXMLogicModuleDefinition](Library-module-example.md)

You can also check for [usages in the FHIR IG Statistics](https://packages2.fhir.org/xig/resource/hl7.fhir.uv.cql|current/StructureDefinition/StructureDefinition-cql-fhirQueryPatternCoverage.json)

### Formal Views of Extension Content

 [Description Differentials, Snapshots, and other representations](http://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#structure-definitions). 

 

Other representations of profile: [CSV](../StructureDefinition-cql-fhirQueryPatternCoverage.csv), [Excel](../StructureDefinition-cql-fhirQueryPatternCoverage.xlsx), [Schematron](../StructureDefinition-cql-fhirQueryPatternCoverage.sch) 



## Resource Content

```json
{
  "resourceType" : "StructureDefinition",
  "id" : "cql-fhirQueryPatternCoverage",
  "extension" : [{
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
    "valueCode" : "cds"
  },
  {
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
    "valueInteger" : 1
  },
  {
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
    "valueCode" : "trial-use"
  }],
  "url" : "http://hl7.org/fhir/uv/cql/StructureDefinition/cql-fhirQueryPatternCoverage",
  "identifier" : [{
    "system" : "urn:ietf:rfc:3986",
    "value" : "urn:oid:2.16.840.1.113883.4.642.40.37.42.18"
  }],
  "version" : "3.0.0-ballot",
  "name" : "CQLFHIRQueryPatternCoverage",
  "title" : "CQL FHIR Query Pattern Coverage",
  "status" : "active",
  "experimental" : false,
  "date" : "2026-08-04",
  "publisher" : "HL7 International / Clinical Decision Support",
  "contact" : [{
    "telecom" : [{
      "system" : "url",
      "value" : "http://www.hl7.org/Special/committees/dss"
    }]
  }],
  "description" : "Describes the extent to which the FHIR query patterns given for a data requirement (i.e. the cqf-fhirQueryPattern extensions present on the data requirement) cover the criteria of that data requirement. Because the query patterns for a data requirement are considered as a set (i.e. the union of the results of the query patterns represents the data for the data requirement), coverage is a characteristic of the data requirement as a whole, rather than of any individual query pattern. A coverage of `total` indicates that no further filtering of the results is required; any other value indicates that the consumer must apply the criteria of the data requirement to the results of the query patterns.",
  "jurisdiction" : [{
    "coding" : [{
      "system" : "http://unstats.un.org/unsd/methods/m49/m49.htm",
      "code" : "001",
      "display" : "World"
    }]
  }],
  "fhirVersion" : "4.0.1",
  "mapping" : [{
    "identity" : "rim",
    "uri" : "http://hl7.org/v3",
    "name" : "RIM Mapping"
  }],
  "kind" : "complex-type",
  "abstract" : false,
  "context" : [{
    "type" : "element",
    "expression" : "DataRequirement"
  }],
  "type" : "Extension",
  "baseDefinition" : "http://hl7.org/fhir/StructureDefinition/Extension",
  "derivation" : "constraint",
  "differential" : {
    "element" : [{
      "id" : "Extension",
      "path" : "Extension",
      "short" : "How completely do the query patterns cover the data requirement?",
      "definition" : "Describes the extent to which the FHIR query patterns given for a data requirement (i.e. the cqf-fhirQueryPattern extensions present on the data requirement) cover the criteria of that data requirement. Because the query patterns for a data requirement are considered as a set (i.e. the union of the results of the query patterns represents the data for the data requirement), coverage is a characteristic of the data requirement as a whole, rather than of any individual query pattern.",
      "comment" : "This extension does not change the expectation that the query patterns for a data requirement are sound, meaning that the union of their results includes all the data described by the data requirement. Criteria that cannot be expressed as search parameters are omitted from the query patterns, rather than approximated with criteria that could exclude required data, and the resulting loss of precision is communicated with this extension. Consuming systems apply the criteria of the data requirement to the results of the query patterns unless the coverage is `total`.",
      "min" : 0,
      "max" : "1"
    },
    {
      "id" : "Extension.extension",
      "path" : "Extension.extension",
      "max" : "0"
    },
    {
      "id" : "Extension.url",
      "path" : "Extension.url",
      "type" : [{
        "code" : "uri"
      }],
      "fixedUri" : "http://hl7.org/fhir/uv/cql/StructureDefinition/cql-fhirQueryPatternCoverage"
    },
    {
      "id" : "Extension.value[x]",
      "path" : "Extension.value[x]",
      "min" : 1,
      "type" : [{
        "code" : "code"
      }],
      "binding" : {
        "strength" : "required",
        "valueSet" : "http://hl7.org/fhir/uv/cql/ValueSet/query-pattern-coverage"
      }
    }]
  }
}

```
