A therapeutic level of heparin should increase the aPTT by what factor?

The therapeutic level of heparin is monitored using the activated partial thromboplastin time (aPTT), which evaluates the intrinsic and common pathways of the coagulation cascade. During heparin therapy, the goal is to achieve a therapeutic effect that significantly prolongs the aPTT compared to baseline levels.

Typically, a therapeutic range for heparin is defined as an increase in aPTT that is 1.5 to 2 times the normal baseline levels. This range indicates effective anticoagulation without excessive risk of bleeding. Therefore, an increase in the aPTT by this factor is crucial for ensuring that heparin is working adequately in preventing thrombosis while maintaining patient safety.

Values outside this range may either indicate inadequate anticoagulation (if the aPTT is less than 1.5 times the baseline) or an increased risk for hemorrhage (if the rise exceeds 2.5 times the baseline). Thus, monitoring and adjusting heparin dosages to stay within this therapeutic range is essential for patient management.