You are asked to consult on a 31-year-old male with prolonged bleeding after an oral surgery procedure. He has no prior history of bleeding diathesis or family history of bleeding disorders. The patient's past medical history is remarkable for infection with the human immunodeficiency virus, with a CD4 count of 51/mL3. The examination is remarkable only for spotty lymphadenopathy. The platelet count is 230,000 cells/mL. His international normalized ratio (INR) is 1.5. Activated partial thromboplastin time is 40 s. Peripheral blood smear shows no schistocytes and is otherwise unremarkable. A 1:1 mixing study corrects both conditions immediately and after a 2-h incubation. Fibrinogen level is normal. Thrombin time is prolonged. What is the diagnosis?
A. Disseminated intravascular coagulation (DIC)
C. Factor V deficiency
D. Liver disease
E. Factor XIII deficiency