The patient with leukemia has acute disseminated intravascular coagulation (DIC) and is bleeding. What diagnostic finding supports this diagnosis?

A. Reduced fibrin split products (FSPs): In DIC, fibrinolysis is increased, producing elevated fibrin degradation products (FDPs or FSPs). A reduction in FSPs would not support the diagnosis, as it indicates minimal fibrin breakdown, which is contrary to the hypercoagulable and consumptive process seen in DIC. B. Elevated D-dimer: D-dimer is a specific fibrin degradation product formed when cross-linked fibrin is broken down by plasmin. In acute DIC, excessive clot formation and simultaneous fibrinolysis lead to markedly elevated D-dimer levels. This finding reflects ongoing coagulation and fibrinolytic activity and supports the diagnosis of DIC. C. Elevated fibrinogen: Fibrinogen is consumed during DIC due to widespread clot formation, leading to low rather than elevated levels. Elevated fibrinogen would suggest an acute-phase response or inflammation, not the consumptive coagulopathy characteristic of DIC. D. Reduced prothrombin time (PT): PT is typically prolonged in DIC because clotting factors are consumed during uncontrolled coagulation. A reduced PT is not consistent with DIC and would indicate faster coagulation than normal, which does not occur in this disorder.