ABSTRACT
Prothrombin Time and Albumin Prothrombin time and serum albumin are true markers of liver synthetic function. Abnormalities of prothrombin time and albumin imply severe liver disease and should prompt immediate evaluation. Prothrombin time is a measure of the activity of factors II, V, VII, and X, all of which are synthesized in the liver. These factors also are dependent on vitamin K for synthesis. Vitamin K deficiency may be produced by antibiotics, prolonged fasting, small-bowel mucosal disorders such as celiac disease, or severe cholestasis with an inability to absorb fatsoluble vitamins. Hepatocellular dysfunction is characterized by an inability to synthesize clotting factors despite adequate stores of vitamin K. A simple way to differentiate vitamin K deficiency from hepatocellular dysfunction in a patient with a prolonged prothrombin time is to administer vitamin K. Administration of vitamin K improves prothrombin time within 2 days in a vitamin K-deficient patient but has no effect if the prolonged prothrombin time is due to liver disease with poor synthetic function.
