This case-insensitive code system http://interopehrate.eu/fhir/CodeSystem/GroupCharacteristic-Code defines the following codes:

Code	Display	Definition
expected lifespan	Expected lifespan	Characteristics with this code constrain the patients expected lifespan
observation	Observation	Characteristics with this code constrain observations of the patient
procedure	Procedure	Characteristics with this code constrain procedures undertaken by the patient
encounter	Encounter	Characteristics with this code constrain encounters that the patient took part in
test	Test	Characteristics with this code define tests the patient must have completed
consent	Consent	Characteristics with this code define the consent document the patient must have signed to