Platelet count is not the primary diagnostic test used to monitor the therapy’s effect of warfarin. Platelets are involved in the clotting process, but warfarin specifically works by inhibiting the synthesis of vitamin K-dependent clotting factors, which does not directly involve platelets.

Choice B rationale

The white blood cell count (WBC) is not used to monitor the effect of warfarin therapy. WBC is typically used to monitor for infection or inflammation, not the coagulation status of a patient.

Choice C rationale

Prothrombin time (PT) is the correct answer. Warfarin therapy is monitored using the PT, which is reported as the International Normalized Ratio (INR). Warfarin inhibits the synthesis of vitamin K-dependent clotting factors, which include Factors II, VII, IX, and X, and Proteins C and S. The PT/INR is sensitive to changes in these factors. An elevated INR indicates a higher risk of bleeding, while a lower INR suggests a higher risk of clotting.

Choice D rationale

Activated partial thromboplastin time (aPTT) is not typically used to monitor warfarin therapy. The aPTT test evaluates the intrinsic and common pathways of coagulation, which includes factors XII, XI, IX, VIII, X, V, II (prothrombin), and I (fibrinogen). Warfarin affects the extrinsic pathway and common pathway, not the intrinsic pathway. Therefore, aPTT is not the best test to monitor the effects of warfarin.

Choice A rationale

Unplugging the cord by holding the plug is a good practice to prevent electrical hazards, but it is not the most important action when administering intravenous fluids.

Choice B rationale

Ensuring the plug has three prongs is the most important action to prevent electrical hazards when administering intravenous fluids. A three-prong plug is grounded and reduces the risk of electrical shock.

Choice C rationale

Avoiding rolling equipment over extension cords is a good practice to prevent electrical hazards, but it is not the most important action when administering intravenous fluids.

Choice D rationale

Plugging in the pump close to the socket is a good practice to prevent electrical hazards, but it is not the most important action when administering intravenous fluids.