Hypercoagulability and DIC are characterized by the presence of SFMC in plasma. We have devised a more rapid method with a quantitative estimation of SFMC by use of HPLC. The normal percentage of SFMC of total fibrinogen content was 2.2 +/- 0.8% in plasma. On the other hand, the amount of SFMC in DIC patients showed a level of 6.8% to 16.7%. The level of SFMC in the third postoperative day after gastrointestinal surgery was between 2.3% and 6.1%. These moderately elevated SFMC levels were suggested to be due to the state of hypercoagulability. Thus, the measurement of SFMC with HPLC is a very useful method to analyze hypercoagulability and DIC.