Question on ProcedureRequest/specimen

Hello,
When creating a specimen resource to poplate it on the ProcedureRequest for a Lab test where would I indicate if the specimen was collected when patient was Fasting or not.

Thanks,
-sri

see http://lists.hl7.org/read/messages?id=327700 - I guess this is an open question still

Also see https://chat.fhir.org/#narrow/stream/4-implementers/subject/Fasting.20Patient for follow ups