The practical nurse (PN) learns in the change-of-shift report that the prothrombin time (PT) and International Normalized Ratio (INR) values are prolonged for a client who is receiving warfarin. The PN should review which additional laboratory test result for the client?

A. Protein: Although low protein levels can influence drug binding and metabolism, they are not directly related to the anticoagulant effects or bleeding risks associated with prolonged PT/INR values. Protein monitoring is not the priority in this context. B. Potassium: Potassium levels reflect electrolyte balance and cardiac function but are not affected by warfarin therapy. Abnormal potassium results would not explain or correlate with prolonged clotting times. C. Hemoglobin: Prolonged PT and INR increase the risk of bleeding, which can lead to anemia. Reviewing hemoglobin levels helps determine whether the client has experienced occult or active blood loss as a result of excessive anticoagulation. D. White blood cell count: WBC count reflects immune system activity and infection status, not coagulation function. It provides no direct information about bleeding risk or the effects of warfarin therapy.