Abstract: Provided are a monoclonal antibody making it possible to detect a native fibrin monomer, which is produced at the initial state of blood coagulation, and soluble fibrin; a hybridoma; and an immunoassay for detecting the initial stage of blood coagulation with high sensitivity, quickly, using the monoclonal antibody. Using a fibrinogen analog in blood as an immune source, cell fusion is carried out to prepare a monoclonal antibody which is not reactive with fibrinogen and is specifically and simultaneously reactive with a native fibrin monomer (that is, a fibrin monomer which is present in a body fluid, in particular in blood, and is not solubilized) and soluble fibrin. The fibrin monomer analog is preferably fibrinogen treated with bathroxobin, which is a snake venom.

Abstract: Provided are a monoclonal antibody making it possible to detect a native fibrin monomer, which are produced at the initial state of blood coagulation, and soluble fibrin; a hybridoma; and an immunoassay for assaying the initial stage of blood coagulation highly sensitively, and promptly, using the monoclonal antibody. Using a fibrinogen analogous compound in blood as an immune source, cell fusion is carried out to prepare a monoclonal antibody which is not reactive with fibrinogen and is specifically and simultaneously reactive with a native fibrin monomer (that is, a fibrin monomer which is present in a body fluid, in particular in blood, and is not solubilized) and soluble fibrin. The fibrin monomer analogous compound is preferably fibrinogen treated with bathroxobin, which is a snake venom.