Measurement of fibrinogen degradation products (FDP) in serum of normal and tumor-bearing rats.

The level of serum fibrinogen degradation products (FDP) in rat was quantified by hemagglutination-inhibition immunoassay which utilized anti-rat-fibrinogen antiserum of rabbit and fibrinogen-coated rat erythrocytes. The sensitivity of this method was high enough to detect minute amounts of serum FDP in rats. The normal value ranged from 1.25 to 10 mug/ml with a mean value of 5.7 mug/ml as expressed as fibrinogen equivalents. The changes in FDP level were noted in tumor-bearing rats which were transplanted subcutaneously with 10(6) tumor cells (AH-109A, a strain of Yoshida rat ascites hepatoma). The FDP level was unchanged in an early stage, elevated to 56 mug/ml on 12th day and to 92 mug/ml on 16th day on an average. These elevations were statistically significant.