Activated Protein-C Resistance (APCR) is a thrombotic disorder associated with increased risk of blood clot formation caused by mutation in the Factor V gene, known as Factor V Leiden mutation. This leads to resistant protein-C, natural anticoagulant to inactivate Factor V, causing hypercoagulable state. Tests are recommended for deep vein thrombosis, pulmonary embolism, and thrombotic events to diagnose and treat.