Due to the manifold functions of tissue factor (TF), also tissue factor pathway inhibitor (TFPI), its endogenous antagonist, is of interest. For the determination of TFPI, either its antigen concentration or its activity can be measured. Method: A chromogenic assay for the functional determination of TFPI is presented and modified for its application in the routine laboratory. Its suitability for daily use was evaluated by testing more than 7000 plasma samples from a heparin study in healthy volunteers. In addition, our data confirm that the method records the activity of both free- and lipoprotein-associated TFPI. Conclusion: The chromogenic assay proved to be rapid and easy to perform and features a high reproducibility. Due to excellent correlation of the results with the total TFPI antigen concentrations, the method represents a more rapid and economic alternative to the determination of total TFPI antigen by ELISA in plasma samples after heparin application.
Print ISSN: 0340-6245
Volume: 25, 01/2005
Pages: 286 - 292