200
The nurse is assessing a client whose warfarin (Coumadin) therapy was discontinued 3 weeks ago. Which laboratory test result indicates that the client’s warfarin therapy is no longer therapeutic?
a. International normalized ratio (INR), 0.9
b. Reticulocyte count, 1%
c. Serum ferritin level, 350 ng/mL
d. Total white blood cell (WBC) count, 9000/mm3
A
Warfarin therapy increases the INR. Normal INR ranges between 0.7 and 1.8. Therapeutic warfarin levels, depending on the indication of the disorder, should maintain the INR between 1.5 and 3.0. When the effects of warfarin are no longer present, the INR returns to normal levels. Warfarin therapy does not affect white blood cell count, serum ferritin level, or reticulocyte count.