Understanding the paradox of factor XII deficiency: A case study on coagulation challenges and surgical management in a patient with isolated activated partial thromboplastin time prolongation

A 32-year-old male was incidentally diagnosed with factor XII (FXII) deficiency after a road traffic accident. He presented with an isolated left ankle fracture requiring surgical fixation. Preoperative evaluation revealed prolonged activated partial thromboplastin time (APTT) with normal prothrombin time and no bleeding history. Mixing studies and factor assays confirmed severe FXII deficiency (<5.8%). Despite abnormal coagulation profiles, the patient underwent surgery without bleeding complications. Fresh frozen plasma was administered preoperatively, although literature suggests it is often unnecessary in FXII deficiency. This case highlights the paradox of FXII deficiency, where laboratory abnormalities do not predict bleeding risk. It emphasizes the importance of accurate coagulation result interpretation in surgical planning and suggests that prolonged APTT alone should not delay necessary interventions. Recognizing this condition can prevent unnecessary treatments and guide perioperative management. This case demonstrates the need for careful consideration of FXII deficiency in surgical patients.