Which test should a nurse use to monitor and regulate heparin therapy for a client with deep vein thrombosis?

The activated partial thromboplastin time (aPTT) test is essential for monitoring and regulating heparin therapy, particularly in patients with deep vein thrombosis (DVT). Heparin acts as an anticoagulant by inhibiting thrombin and factor Xa, thereby prolonging the time it takes for blood to clot. The aPTT specifically measures the intrinsic and common pathways of coagulation and helps determine the effectiveness and safety of heparin therapy.

When a patient is receiving heparin, the aPTT should be periodically checked to ensure that it remains within the therapeutic range, which is typically 1.5 to 2.5 times the normal aPTT value, depending on the protocol. This monitoring is crucial because it helps prevent both inadequately anticoagulated states (which can lead to thromboembolic events) and excessively anticoagulated states (which can increase the risk of bleeding).

The other tests mentioned, such as prothrombin time (PT), international normalized ratio (INR), and complete blood count (CBC), serve different purposes in assessing coagulation and overall health but are not appropriate for specific monitoring of heparin therapy. PT and INR are primarily used for monitoring oral anticoagulants