This code system http://terminology.hl7.org/CodeSystem/allerg-intol-substance-exp-risk defines the following codes:

CodeDisplayDefinition
known-reaction-risk Known Reaction RiskKnown risk of allergy or intolerance reaction upon exposure to the specified substance.
no-known-reaction-risk No Known Reaction RiskNo known risk of allergy or intolerance reaction upon exposure to the specified substance.
 <status value="draft"/> <experimental value="false"/> <date value="2020-04-09T21:10:28+00:00"/> <publisher value="HL7 (FHIR Project)"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> <telecom> <system value="email"/> <value value="fhir@lists.hl7.org"/> </telecom> </contact> <description value="The risk of an adverse reaction (allergy or intolerance) for this patient upon exposure to the substance (including pharmaceutical products)."/> <caseSensitive value="true"/> <valueSet value="http://terminology.hl7.org/ValueSet/allerg-intol-substance-exp-risk"/> <content value="complete"/> <concept> <code value="known-reaction-risk"/> <display value="Known Reaction Risk"/> <definition value="Known risk of allergy or intolerance reaction upon exposure to the specified substance."/> </concept> <concept> <code value="no-known-reaction-risk"/> <display value="No Known Reaction Risk"/> <definition value="No known risk of allergy or intolerance reaction upon exposure to the specified substance."/> </concept> </CodeSystem>