Detection of cross-linked fibrin derivatives.

Results show the time course of ancrod treatment of all 12 subjects (mean, SD, 95th percentile). (A) D-dimer measured by Dimertest gold ELISA. (B) D-dimer measured by STA LIAtest D-di LPIA. (C) D-dimer measured by TINAquant D-dimer LPIA. Fibrin degradation product D-dimer is generated by plasmin degradation of factor XIIIa–cross-linked fibrin. Two D-dimer antigen assays, STA-Liatest D-di, and AGEN Dimertest gold, showed a gradual increase in D-dimer antigen in response to ancrod infusion, with highest levels 6 hours after start of infusion, followed by a gradual decrease. Similar to fibrin(ogen) degradation product assays, there was a 1-hour lag phase. Two other assays in clinical use for the detection of D-dimer antigen displayed no appreciable increase in D-dimer antigen concentration. Results of TINAquant D-dimer assay are shown in panel C. Values of both assays remained within the normal range throughout the experiment, indicating that the antigenic compounds detected by these assays are dissimilar to those of the former D-dimer antigen assays.