An 81-year-old male with arteriosclerosis and a long-standing history of taking Coumadin presents to his physician's Office for his biweekly prothrombin time (PT) test. The PT test is one of the most common hemostasis tests used as a presurgery screening and monitoring Coumadin (warfarin) therapy. This test evaluates
A. coagulation of the blood.
B. the iron-binding capacity of RBCs.
C. the oxygen-carrying capacity of RBCs.
D. the type and cross-match of blood.
Answer: A