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Updated: May 8, 2026

Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
Usefulness of laboratory values in predicting effectiveness of recombinant factor VIIa in surgical patients with
Sarah N Gruber1, David F Volles
1Department of Pharmacy, University of Virginia Health System, Charlottesville, VA, USA. sg9pq@virginia.edu
Purpose:
The results of a study to determine whether certain laboratory values can predict the effectiveness of recombinant factor VIIa (rFVIIa) therapy to control postoperative bleeding in surgical patients are presented.
Methods:
In a retrospective observational study at a large university hospital, the records of all adult patients on the cardiothoracic surgery (CTS) and general or trauma surgery (GTS) units who received rFVIIa for treatment-refractory nonsurgical bleeding episodes (an off-label use) during a 17-month period were reviewed. Collected data included blood product requirements before and after administration of rFVIIa, selected periadministration laboratory values (e.g., International Normalized Ratio, platelet count, arterial pH, fibrinogen concentration), 24-hour and 30-day mortality, and documented adverse thrombotic events.
Results:
Among the 18 GTS and 32 CTS patients who received rFVIIa during the study period, hemostasis (as defined according to 12- and 24-hour transfusion requirements) was achieved in 50% of patients in both groups. Two of the evaluated laboratory values were found to be predictive of reduced rFVIIa effectiveness. Hemostasis was not achieved in any patient with an arterial pH of ≤7.1 or a fibrinogen concentration of <100 mg/dL. The study results did not support the hypothesis that a platelet count of <50,000 cells/L is associated with reduced effectiveness of rFVIIa therapy for the studied indication. Adverse thrombotic events occurred in 14 patients (28%) after rFVIIa administration.
Conclusion:
CTS and GTS patients with bleeding episodes and an arterial pH of ≤7.1 or a fibrinogen concentration of <100 mg/dL were not likely to achieve hemostasis after rFVIIa therapy.
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