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Updated: Jun 26, 2026

A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time
Published on: February 14, 2017
Intrinsic hemostasis activation by freezing and thawing of plasma
Thomas W Stief1, Stefanie Otto, Harald Renz
1Department of Clinical Chemistry, University Hospital Giessen & Marburg, Germany. thstief@med.uni-marburg.de
Abstract:
Low-grade contact activation of hemostasis is clinically relevant. Freezing/thawing of plasma was studied in the intrinsic coagulation activity assay. Normal plasmas were frozen at -80 degrees C or -20 degrees C and thawed at 37 degrees C or 23 degrees C. These plasmas and unfrozen samples were activated by SiO2 -CaCl2. Freezing/thawing of normal plasma induced about 100-fold more thrombin activity at 5 minutes coagulation reaction time than the respective unfrozen samples. Freezing at -80 degrees C induces more artificial changes than freezing at -20 degrees C. In 9 of 10 plasmas of patients receiving coumarin, nearly no additional thrombin is generated within a 12-minute coagulation reaction time. Minor procoagulant changes of plasma might be dangerous in patients with insufficient liver function, who might not tolerate a therapy with fresh frozen plasma, which behaves as a procoagulant because of its matrix changes. The intrinsic coagulation activity assay allows the measurement of low-grade contact activation of frozen/thawed plasma.
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