Research PapersA comparative study of functional assays for tissue factor pathway inhibitor using normal plasma and clinical samplesAdams, M. J.; Oostryck, R.Author Information The authors are with the School of Biomedical Sciences, Curtin University of Technology, Perth, Australia. Received 30 September 1999; revised 1 February 2000; accepted 7 February 2000) Address correspondence to: R. Oostryck, School of Biomedical Sciences, Curtin University of Technology, GPO Box U 1987, Perth 6845, Australia. Tel: (+61) 8 9266 7518; fax: (+61) 8 9266 2342; e-mail: [email protected] Blood Coagulation and Fibrinolysis: June 2000 - Volume 11 - Issue 4 - p 327-333 Buy Abstract Tissue factor pathway inhibitor (TFPI) is a Kunitz-type inhibitor that regulates the initiation of tissue factor-mediated coagulation. Recent reports in the literature have described variable results using different methodologies for TFPI measurement. In this study, we used one clotting and two amidolytic methodologies to assess TFPI functional levels. The study groups included normal healthy donors as well as patients with acute hepatitis, diabetes, coronary artery bypass graft operations, deep vein thrombosis, and prior to and during heparin therapy. The aims were to compare the results obtained in normal plasma using different assay systems, to compare TFPI levels in a range of clinical samples, including those previously not determined using a clotting methodology, and to report TFPI levels in patient groups previously not investigated. The results clearly demonstrate poor correlation between functional TFPI values using the different methodologies, highlighting the requirement for standardization. © 2000 Lippincott Williams & Wilkins, Inc.