Activation of factor VII in the extrinsic pathway
decreased platelet production, aplastic anemia, leukemia, chemotherapy, bleeding, splenomegaly, platelet alloantibodies
Quality of circulating platelets
Hepatic disease, uremia, bleeding, consumptive process of excess clot formation
Hepatic disease, vitamin K deficiency, malabsorption syndrome, antibiotic depletion of normal flora, bleeding loss of factor VII, coumadin derivatives
150-400mg/dl
Presence of thrombin inhibitor, abnormal fibrinogen
<10mcg/mL or negative at 1:1000 dilution
Hepatic failure, found approxiamately 2-3 days after large clot formation, excessive clotting disease (DIC)
4-5 minutes
10-15 seconds
Factor VIII deficiency, hepatic disease, presence of thrombin inhibitors, blood loss of coagulation factors
Quantity of circulating fibrinogen (not quality)
Presence of platelet inihibitors, uremia, hyperammonemia, Von Willebrand's disease
11-16 seconds
150,000-400,000
Ability of platelets to form platelet plug
Determines amount of byproducts from lysed clots present in circulation; the d-dimer fragment can be measured to better determine whether the patient is experiencing DIC
Conversion of prothrombin time to thrombin
30-45 seconds
Conversion of thrombin and fibrinogen to fibrin
