The postoperative phase can be associated with an increased risk of thrombosis and abnormal bleeding. We report the case of a patient admitted to our intensive care unit for postoperative monitoring who developed two episodes of hemorrhagic shock. A thromboelastogram performed with heparinase I digestion demonstrated the action of endogenous heparin-like substances whose presence was subsequently confirmed at the histological examination of the tumor. Heparinase-modified thromboelastography has proven to be an effective and rapid point-of-care coagulation test and in our case allowed early detection of circulating heparinoids.