Semiquantitative determination of soluble fibrin monomer complexes by chromatography and serial-dilution protamine...

Plasmas were prepared from blood obtained from rabbits and from healthy individuals and patients with thrombotic disorders. Gel filtration (Sepharose-4B) chromatography and the serial-dilution protamine sulfate (SDPS) test were performed on each sample. For healthy individuals and rabbits, a narrow fibrinogen peak was obtained on chromatogram and was associted with a negative SDPS test. After administration of thrombin or endotoxin to rabbits and in plasmas from patients with intravascular coagulation, major shifts to earlier effluent volumes occurred. These higher-molecular-weight derivatives corresponded to soluble fibrin monomer complexes (FM). Positive SDPS tests were found in these plasmas. There was a highly significant correlation between percentage area occupied by FM on chromatogram and SDPS test titer. It is concluded that the SDPS test is a reliable semiquantitative measure of FM that can be used clinically as well as in experimental animal models.