Sensitive detection of the activation state of blood coagulation in porcine DIC models by a new fibrin immunoassay

Elevated levels of soluble fibrin in plasma indicate that thrombin converts fibrinogen to fibrin without sufficient inhibitory control. Therefore, measurement of soluble fibrin (SF) in plasma may be considered as a laboratory test for intravascular coagulation. We have demonstrated that a new immunoassay for detection of SF in human plasma (Lill et al., Blood Coag Fibrinol 1993; 4: 97-102), based on a fibrin specific monoclonal antibody, also detects porcine SF with high sensitivity. Thrombin-dependent generation of SF in porcine plasma in vitro resulted in increased reactivity of the assay system, which was time and dose dependent. Dextran sulphate (DXS) and bacterial lipopolysaccharide (LPS) were used as stimuli in in vivo experiments in pigs. Plasma levels of SF increased steadily after intravenous administration of DXS (5 mg/kg for 1 h) to 38 ± 7.8 μg/ml (mean ± SEM) at 2 h, whereas LPS (2 μg/kg/h for 6 h) markedly increased plasma SF levels to over 120 μg/ml (at 6 h) after a lag phase of 2 h. In conclusion, this new immunoassay for human fibrin allows specific and sensitive detection of soluble fibrin in porcine plasma.