What lab value is monitored for patients on heparin therapy?

For patients on heparin therapy, the lab value that is primarily monitored is the activated partial thromboplastin time (aPTT or PTT). Heparin is an anticoagulant that works by enhancing the action of antithrombin III, leading to inhibition of thrombin and factor Xa in the coagulation cascade. The PTT assesses the intrinsic pathway of coagulation and is crucial for evaluating how well the blood coagulation process is functioning under the influence of heparin.

Monitoring the PTT allows healthcare providers to ensure that the patient is within the therapeutic range for anticoagulation. This is essential because if the PTT is too low, the patient may be at risk for thromboembolic events, while if it is too high, the patient could be at risk for excessive bleeding.

Other lab values like PT (prothrombin time) and INR (International Normalized Ratio) are more relevant for patients on warfarin therapy, which acts on the extrinsic pathway of coagulation, rather than heparin. Glucose levels are unrelated to anticoagulation status and are monitored for other clinical reasons, such as diabetes management. Thus, monitoring the PTT is the appropriate and critical lab value for patients receiving