Acquired Factor XIII Deficiency in a 19-year-Old Male Following Ballistic Injury.

Factor XIII deficiency is a rare cause of post-operative bleeding. It poses a diagnostic challenge as standard coagulation tests including prothrombin time, international normalized ratio, and activated partial thromboplastin time are usually normal in factor XIII deficiency. We present the case of our patient, a 19-year-old male with acquired factor XIII deficiency diagnosed after ballistic injury with a post-operative course complicated by hemorrhage. This case demonstrates an uncommon cause of coagulopathy, acquired factor XIII deficiency, and the challenges it poses to post-operative management. The diagnosis of acquired factor XIII deficiency may be challenging, but a high clinical suspicion is imperative to avoid a missed diagnosis and delayed treatment.