The amount of a guanine nucleotide-binding protein G(i) subunit alpha-3 (human) when measured in cerebrospinal fluid. The trait is level of guanine nucleotide-binding protein G(i) subunit alpha-3 (human) in cerebrospinal fluid (OBA_2056910). Also known as: cerebrospinal fluid guanine nucleotide-binding protein G(i) subunit alpha-3 (human) amount.