Science has become politicized, and that's an embarrassment. —Seth MacFarlane
Fibrinogen is a large protein manufactured by the liver and released continuously into blood. It is the precursor of both soluble fibrin and insoluble fibrin. It cannot escape the intact vascular system.
Fibrinogen has no effect on blood viscosity or coagulabiliity, but it is an essential precursor for coagulation and can become depleted due to prolonged surgery and severe trauma, causing a generalized paralysis of hemostasis (coagulation and capillary hemostasis) called "Disseminated Intravascular Coagulation" (DIC).
During World War I the French army developed a plasma substitute consisting of freeze-dried fibrinogen that was used as an emergency blood substitute. Similar products remain available in France, but are unheard of in North America. Such a product would provide an inexpensive and convenient alternative to fresh frozen plasma if it were available. It could be used to quickly re-constitute fresh-frozen packed red blood cells so as to provide a safe, convenient and cheap blood replacement free of bacterial contamination or allergic potential.