Abstract: The invention relates to a method of a preparation of monoclonal antibody derived from a crosslinked fibrin derivative including the steps of:(i) obtaining a crosslinked fibrin derivative or extract containing same; and(ii) forming an antibody to said derivative or extract by cloning antibody producing cells from an animal having been administered thereto said derivative or extract.A screening assay for use in the abovementioned method which includes the steps of:(A) coating a surface with an antigen selected from a(i) crosslinked fibrin derivative;(ii) extract containing said derivative; or(iii) fibrinogen degradation product.