This is the ValueSet that contains all the codes in eHDSI Absent Or Unknown Allergy (http://terminology.ehdsi.eu/ValueSet/eHDSIAbsentOrUnknownAllergy) and eHDSI Absent Or Unknown Allergy (http://terminology.ehdsi.eu/ValueSet/eHDSIAbsentOrUnknownAllergy). E.g. what you have to deal with if you get resources containing codes in either of them