SYNOPSIS Factor VII levels have been measured in 100 patients with liver disease following parenteral vitamin K1 therapy. There was good agreement between specific factor VII measurements and the one-stage prothrombin time apart from six patients with compensated cirrhosis in whom the prothrombin time was prolonged despite the presence of normal factor VII levels. A mean activity of 58 % was found in patients with cirrhosis. Cirrhotic patients with features of hepatic decompensation had a significantly lower mean level of activity (40 %) than the 'contrast' patients with surgical obstruction of the major bile ducts (93 %). Patients with chronic active liver disease had moderate depression of factor VII levels and those with non-cirrhotic alcoholic liver damage had mean activities similar to the contrast group.Factor VII levels could not be correlated with BSP retention but there was a correlation with serum albumin concentration.It is concluded that the prothrombin time using the Quick test with a standardized thromboplastin showing good sensitivity to factor VII, eg, the Manchester reagent (BCT), provides a reliable index of coagulability in chronic liver disease, and specific factor VII assays are not indicated.The liver is the major site of synthesis of many clotting factors (Roberts and Cederbaum, 1972) and it is not unexpected that reduced levels of these have been reported in liver disease (Owren, 1949;Hallen and Nilsson, 1964;Donaldson et al, 1969).Biochemical tests of liver function have traditionally been used to assess and monitor the progress of patients with hepatic disorders. More recently, both broad-spectrum tests of blood clotting, ie, onestage prothrombin time and partial thromboplastin time and specific clotting factor measurements, particularly factor VII assays (Dymock et al, 1975), have proved of additional value in the diagnosis and assessment of liver disease. When measuring factor VII levels most workers have had to rely on combined assays such as the P and P test and Normotest (Hillenbrand and Sherlock, 1973;Henning and Yano, 1973) which are affected by deficiencies of other clotting factors, eg, factors II and X as well as factor VII. However, the availability of a naturally occurring factor VII deficient plasma in beagle dogs (Poller et al, 1971) has provided a standardized specific clotting factor VII assay. Its importance in accurately reflecting the state of hepatic function in