Evaluation of the Accuracy of the INRatio Prothrombin Time (PT) Monitoring System With a New Test Strip for the Oral Anticoagulation Therapy Patient in the Presence of Heparin and Low Molecular Weight Heparin (e.g., Enoxaparin or Dalteparin)

This is a multi-center study designed to evaluate the heparin insensitivity of the INRatio
Prothrombin Time (PT) Monitoring System, utilizing an INRatio test strip additionally
modified for low sample volume. The INRatio test strip is used for the quantitative
determination of PT and International Normalized Ratio (INR) results in fingerstick blood
from subjects on oral anticoagulation therapy (OAT) with warfarin. This study is designed
to evaluate the accuracy of the modified INRatio test strip during heparin-warfarin bridge
therapy with unfractionated heparin (UH) or low molecular weight heparin (LMWH), such as
enoxaparin or dalteparin. These INR results will be compared to the INR results obtained on
plasma from the same subjects as analyzed at a central laboratory with the
heparin-insensitive reference method: the Sysmex CA-560 System. The levels of UH or LMWH in
the plasma samples will be assessed using activated partial thromboplastin time (aPTT) and
anti-factor-Xa assays respectively.