Scientific Publications by FDA Staff

J Thromb Haemost 2015 Aug;13(8):1527-30

No effect of corn trypsin inhibitor on factor XIa-dependent thrombin generation assay: comment.

Parunov LA, Surov SS, Tucker E, Ovanesov MV

Corn trypsin inhibitor (CTI) is a well-characterized inhibitor of coagulation Factor (F) XIIa that is commonly used as a reagent in the tissue factor (TF)-activated global hemostasis assays, Thrombin Generation Test (TGT) and Thromboelastography (1-3). CTI was shown to improve assay reproducibility (4) presumably because CTI inhibits spontaneous plasma activation caused by contact with collection tubes, pipette tips, storage vials and experimental cuvettes. The effect of CTI against contact artifacts is concentration-dependent from 5 up to a saturation concentration of 100 µg/mL, and therefore 100 µg/mL or more CTI is widely used in experiments (5). Although spontaneous contact activation can also be mitigated by higher concentrations of TF (>5 pM), low TF (=1 pM) and hence CTI are required in certain situations (4), e.g., for evaluation of FIX, FVIII and FXI deficiencies.