A performance evaluation of a novel human recombinant tissue factor prothrombin time reagent (Revohem™ PT)

Introduction: A new prothrombin time reagent (Revohem (TM) PT) based on recombinant human tissue factor produced by the silkworm-baculovirus expression system was tested. The aim of this study was to compare the performance of the new PT reagent with two widely used routine PT reagents. Methods: All testing was performed on a Sysmex CS-5100 coagulometer. Revohem (TM) PT was tested for imprecision and stability using normal and abnormal lyophilized commercial control plasmas. Comparability was assessed with two widely used reagents: one containing recombinant human tissue factor (Reagent A) and the other a human placental thromboplastin (Reagent B) using a wide range of normal and abnormal plasmas and analyser-specific ISI values. Results: Excellent between-day imprecision was obtained for Revohem (TM) PT (CV <1.0%) and acceptable open-vial on-board stability over 7days. There was good agreement between methods in samples from patients with liver disease and patients receiving warfarin and no significant differences between methods with increasing INR values. Both recombinant reagents suffered less interference from lupus anticoagulant than the placental thromboplastin. Revohem (TM) PT had similar sensitivity to reagents A and B for FII, V, VII and X deficiency and demonstrated dose responsiveness to dabigatran, apixaban and rivaroxaban with steeper response curves than the comparison reagents. Conclusion: Revohem (TM) PT showed comparable or improved performance relative to two widely used reagents and is suitable for use in warfarin control, detection of inherited factor II, V, VII and X deficiency and assessment of liver disease coagulopathy.