This code system http://hl7.org/fhir/substance-optical-activity defines the following codes:

Code Display
+ dextrorotary
- levorotary
<status value="active"/> <experimental value="false"/> <date value="2021-01-05T10:01:24+11:00"/> <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 optical rotation type of a substance."/> <jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <caseSensitive value="true"/> <valueSet value="http://hl7.org/fhir/ValueSet/substance-optical-activity"/> <content value="complete"/> <concept> <code value="+"/> <display value="dextrorotary"/> </concept> <concept> <code value="-"/> <display value="levorotary"/> </concept> </CodeSystem>