Related Experiment Video
Updated: Apr 24, 2026

Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
The effect of recombinant and plasma-derived prothrombin on prothrombin time in human plasma
K M Hansson1, J Björkqvist, J Deinum
1Department of Bioscience, CVMD iMED, AstraZeneca R&D Mölndal, Mölndal, Sweden.
Introduction:
When investigating coagulation assays to measure the effect of infused prothrombin (FII) in in vivo coagulopathy models, we found that addition of FII, plasma-derived human FII (pd-hFII) or recombinant human FII (r-hFII), to normal plasma resulted in a concentration-dependent increase in prothrombin time (PT) initiated with Innovin(®) .
Methods:
The effect on PT by addition to plasma of either pd-hFII or r-hFII, using different commercial PT reagents, was studied both by turbidimetry and viscometry.
Result:
Addition of FII to plasma resulted in increased PT when initiated with Innovin(®) : PT increased with 20% by doubling the concentration. The prolongation of PT became more pronounced with 2-6000 times diluted Innovin(®) . However, by adjustment of the final free Ca(2+) concentration in the assay with diluted Innovin(®) from 8.3 to 1.3 mmol/L, no FII-dependent increase in PT was found. In contrast, no prolongation of PT was found with other commercial PT reagents. A KM = 3 nmol/L was obtained with pd-hFII, respectively, r-hFII with FII-depleted plasma using Thromborel(®) to initiate PT.
Conclusion:
At normal plasma concentration of FII, addition of FII should not have an effect on PT. The prolonged PT with Innovin(®) , but not with other PT reagents, at supranormal FII concentration is an artefact.
More Related Videos
06:59The Nijmegen Hemostasis Assay: Simultaneous Fluorogenic Measurement of Thrombin and Plasmin Generation in a Single Well
Published on: February 27, 2026
09:38A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time
Published on: February 14, 2017
Related Concept Videos
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Venous Thrombosis III: Interprofessional Care
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
Clot Retraction and Fibrinolysis
Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants
Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...
Coagulation
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...