A nurse is caring for a client who is receiving heparin therapy. Which laboratory test should the nurse monitor to determine the effectiveness of the medication?

“I should report any unusual bleeding or bruising to my provider.” This statement indicates that the client understands that warfarin is an anticoagulant that can increase the risk of bleeding and that any signs of bleeding should be reported promptly.Warfarin works by inhibiting the synthesis of vitamin K-dependent clotting factors, so the client should monitor their intake of vitamin K, but not avoid it completely.Warfarin can be taken with or without food, so choice B is not correct.

Aspirin is also an anticoagulant and can increase the risk of bleeding when taken with warfarin, so the client should avoid taking it unless prescribed by the provider

Activated partial thromboplastin time (aPTT) is the laboratory test most commonly used to monitor the anticoagulant effect of unfractionated heparin therapy. The aPTT measures the time it takes for blood to clot in the presence of heparin, which inhibits thrombin and other clotting factors.The aPTT should be maintained at 1.5 to 2.5 times the normal range, which is usually 25 to 35 seconds.

Choice B is wrong because prothrombin time (PT) is the laboratory test used to monitor the anticoagulant effect of warfarin, not heparin.

Warfarin inhibits the synthesis of vitamin K-dependent clotting factors, such as factor II, VII, IX, and X.The PT should be maintained at 1.5 to 2 times the normal range, which is usually 11 to 13 seconds.

Choice C is wrong because international normalized ratio (INR) is a standardized way of reporting the PT results, which are affected by different reagents and methods.

The INR is used to monitor warfarin therapy, not heparin therapy.The INR should be maintained at 2 to 3 for most indications of warfarin therapy.

Choice D is wrong because platelet count is not a direct measure of the anticoagulant effect of heparin, but rather a potential complication of heparin therapy.

Heparin can cause heparin-induced thrombocytopenia (HIT), a serious condition that causes low platelet count and increased risk of thrombosis.Platelet count should be monitored regularly during heparin therapy to detect HIT, which usually occurs within 5 to 10 days of exposure.The normal platelet count range is 150,000 to 450,000 per microliter of blood.