Fibrinogen titer as an indicator of physiologic stability

A semimicro method was developed and used to determine the levels of fibrinogen in two groups of dogs. One group was obtained from the dog pound and their plasma fibrinogen levels were determined immediately. The other group was kept in the departmental animal quarters under conditions essentially free of environmental stress for 45 days before determining the plasma fibrinogen concentration. The concentration of fibrinogen was found to be significantly lower in the group which was housed in the departmental quarters. However, when representative individuals from the latter group were subjected to intermittent electrical stimuli of low intensity for periods of 3–11 days the plasma fibrinogen increased significantly. It thus appears that the concentration of plasma fibrinogen is directly related to the degree of stress to which animals have been subjected and the stress initiating the response need not cause overt tissue damage.