Activated Clotting Time

Activated clotting time (ACT) is a point-of-care coagulation test designed to monitor heparin therapy in the clinical situations in which intensive anticoagulation is required. This test measures how long it takes your blood to clot. It’s often used to check how well a medicine called heparin is working. Heparin slows the ability of blood to clot, and the ACT test helps your healthcare provider find the right dosage. The ACT is exclusively used to monitor anticoagulation with high doses of UFH (e.g., during cardiac bypass surgery or interventional vascular procedures) because high concentrations of UFH result in an unclottable aPTT. A baseline ACT should be obtained on all patients before UFH administration.