[Biological significance of fibrinopeptide A elevation in the blood].

In 13 patients with effusions of varying etiology, considerably higher fibrinopeptide A (FPA) immunoreactivity were found in the effusions than in the corresponding plasmas. After instillation of heparin into the effusion the FPA concentration diminished significantly but very slowly. The difference in concentration between plasma and effusion therefore represents a relative FPA accumulation in the effusion. In view of its extremely short half-life in plasma, the FPA produced in the effusions is thought not to contribute to the increased plasma FPA levels. In addition, injection of amounts of FPA into the effusion such as to produce an acute increase of the local FPA level did not lead to a significant change in the FPA level in plasma.