Working from LogicaHealth IG
Modifier extension adding certainty of absence. See https://covid-19-ig.logicahealth.org/StructureDefinition-covid19-symptoms-absent.html ('Refuted' as a value is being discussed by the HL7 Patient Care Workgroup - steward of the Condition Resource). LBI: Clinical Assessment 2.3 contains some verification values.
See analysis spreadsheet by Linda Bird
| FHIR element | Binding | Comments |
|---|---|---|
| Condition.code | COVID 19 Signs and Symptoms Value Set | |
| Condition.modifierExtension:certaintyOfAbsence | CertaintyOfAbsenceVS | Does the existence of the modifier change the interpretation of the Condition instance? See https://www.hl7.org/fhir/extensibility.html#modifierExtension http://hl7.org/fhir/R4/condition.html#9.2.3.4 and http://hl7.org/fhir/R4/condition.html#9.2.3.5 |