The amount of a amyloid-beta A4 precursor protein-binding family B member 3 (human) when measured in cerebrospinal fluid. The trait is Ontology of Biological Attributes entry OBA_2056529 (level of amyloid-beta A4 precursor protein-binding family B member 3 (human) in cerebrospinal fluid). Also known as: cerebrospinal fluid amyloid-beta A4 precursor protein-binding family B member 3 (human) amount.