A method for preparing thrombin serum , the method comprising obtaining blood fluid sample , contacting a first aliquot of the blood fluid with a procoagulant agent to form prothrombinase enzyme complex bound to the surface of the procoagulant agent so as to obtain an activated procoagulant agent that may be stored. The activated procoagulant agent may then be contacted with a second aliquot of the blood fluid containing prothrombin so as to obtain thrombin serum , which may be extracted and contacted with fibrinogen to obtain fibrin.