Coagulation and fibrinolytic activity of cerebrospinal fluid.

Fibrin/fibrinogen degradation products (fragments D and E) were detected in cerebrospinal fluid in 23.4% of 252 patients admitted to a neurological/neurosurgical unit. Other coagulation proteins of low molecular weight (plasminogen and factor IX) were also present but larger proteins (fibrinogen and factor V) were not. These findings are consistent with protein leakage across a blood-CSF barrier damaged by inflammatory, vascular, or neoplastic disease. Fibrin/fibrinogen degradation products in cerebrospinal fluid after subarachnoid haemorrhage may not, therefore, be a reliable index of increased fibrinolytic activity in the subarachnoid space and may be misleading when selecting patients for fibrinolytic blockade.