Hemostatic alterations in non-cirrhotic portal fibrosis, extrahepatic portal venous obstruction and Budd-Chiari syndrome. 
We studied the coagulation function in ten patients each with non-cirrhotic portal fibrosis (NCPF), extrahepatic portal venous obstruction (EHPO) and Budd-Chiari syndrome (BCS), conditions where venous thrombosis in the hepatic vasculature is a common denominator.  Prothrombin time, partial thromboplastin time with kaolin (PTTK) and thrombin time were normal in patients with NCPF and EHPO.  However, in BCS the PTTK was prolonged, with a mean test/control ratio of 1.68 +/- 0.11.  Fibrin degradation products were absent in all patients.  Platelet aggregation tests showed hypoaggregability in all patients with NCPF.  They were normal in patients with EHPO.  However, two of ten BCS patients showed hyperaggregability, coinciding with a recent onset of illness in one patient.  In conclusion, coagulation abnormalities appear unlikely to be the cause of thrombosis in patients with NCPF and EHPO.  Further studies are required to substantiate the findings of hyperaggregability of platelets in BCS.