This case-sensitive code system http://hl7.org/fhir/us/cdmh/CodeSystem/pcornet-result-loc defines the following codes:

Code	Display	Definition
L	Lab	Location of the test result is Lab.
P	Point of Care	Point of Care locations may include anticoagulation clinic, newborn nursery, finger stick in provider office, or home.
NI	No information	Location of the test result has No information.
UN	Unknown	Location of the test result is Unknown.
OT	Other	Location of the test result is Other.