<status value="draft" /> <fhirVersion value="4.0.0" /> <kind value="resource" /> <abstract value="false" /> <type value="Observation" /> <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Observation" /> <derivation value="constraint" /> <differential> <element id="Observation"> <path value="Observation" /> </element> <element id="Observation.extension"> <path value="Observation.extension" /> </element> <element id="Observation.extension:age-at-event"> <path value="Observation.extension" /> <sliceName value="age-at-event" /> <sliceIsConstraining value="false" /> <label value="age_at_event" /> <short value="Age time of event" /> <definition value="Age (in days since birth) of the Participant at time of vital status observation" /> <min value="0" /> <max value="1" /> <type> <code value="Extension" /> <profile value="http://fhir.kids-first.io/StructureDefinition/age-at-event" /> </type> <isModifier value="false" /> </element> <element id="Observation.subject"> <path value="Observation.subject" /> <min value="1" /> </element> <element id="Observation.value[x]"> <path value="Observation.value[x]" /> <min value="1" /> </element> </differential> </StructureDefinition>