Patients with inflammatory bowel diseases (IBD), a chronic inflammatory disease characterized by flares and remission, are prone to develop thrombosis. The mechanism behind this prothrombotic state is not completely understood but is definitely multifactorial and linked with excessive inflammation observed in these patients. So far, no biomarker exists to select among IBD patients those with and increased risk for thrombosis. Corticosteroid therapy, given as rescue IBD treatment, is known to increase the thrombotic risk, whereas for antitumor necrosis factor (TNF)-alpha therapy such as infliximab, given to induce and maintain remission in IBD, the results are inconclusive. Here, we describe a 31-year-old IBD patient who developed a deep vein thrombosis. We determined the clot lysis profiles before and after developing thrombosis. We showed that a global functional clot lysis assay can be used as a tool to identify IBD patients who may benefit from thromboprophylactic therapy.