The amount of a Kunitz-type protease inhibitor 3 (human) when measured in cerebrospinal fluid. The trait is level of Kunitz-type protease inhibitor 3 (human) in cerebrospinal fluid (OBA_2057945, an Ontology of Biological Attributes id). Also known as: cerebrospinal fluid Kunitz-type protease inhibitor 3 (human) amount.