A Patient Is Stabilized on Warfarin with an International Normalized

Multiple Choice

A patient is stabilized on warfarin with an international normalized ratio (INR) of 2.7.He develops pneumonia and is admitted to the hospital.His appetite is depressed and he is placed on broad-spectrum antibiotic agents.At 1 week after the admission,his INR is 5.0.What is the most likely interpretation?

A) The patient should be given more warfarin.
B) A PTT should be performed to rule out heparin administration.
C) A new sample should be collected to rule out a clotted specimen.
D) Vitamin K is reduced, increasing the effects of warfarin.