Selection

Body:

Attributes:

Contained in:

The Selection element provides a template for machine-readable/executable expressiosn for retrieving the data or information from an external resource.

The Path attribute provides the machine-executable instruction or template for it to obtain the data or information from the resource. Depending on the representation of the resource, this can e.g. be an XPath expression (for e.g. ODM, HL7-CDA or HL7-FHIR represented as XML), a JSONPath expression when the resource is represented as JSON, a FHIRPath expression for the case of HL7-FHIR.
The value of the Path attribute can either be an absolute path, or a relative path starting from the information in the "Name" and "Attribute" attributes of the parent Resource element.

It is recommended that the path expression is governed by an international standard.

TODO?: should we add what "language" the "Path" is expressed in?

Examples:
ODM - XPath (absolute path): /ODM/ClinicalData[@StudyOID="AnotherStudy"][@MetaDataVersionOID="MV.001]//ItemData[@ItemOID="IT.BIRTHDATE"}/@Value
leads to the birth date for the given subject as captured in study with OID "AnotherStudy" and MetaDataVersion with OID "MV.001"
HL7-FHIR - relative FHIRPath with "Resource/@Name='Observation' and "Resource/@Attribute='valueQuantity.value":
coding.code(where system='http://loinc.org' and code='6299-2').text
leads to the name of the test for the LOINC code 6299-2, which is e.g. "Urea Nitrogen".