fi·brin·o·gen 
(fī-brĭnə-jən)
(fī-brĭnə-jən)n.
A protein in the blood plasma that is essential for the coagulation of blood and is converted to fibrin by the action of thrombin in the presence of ionized calcium.
fi′bri·noge·nous (fī′brə-nŏjə-nəs) adj.