Summary
1. It was found that effects of deliberate changes in fibrinogen concentration and
in the amount of FDP added to the experimental system (containing pure fibrinogen
solution and saline- or serumdiluted plasma) could be approximated with satisfactory
accuracy by a linear plot of the logarithm of clotting times versus the inverse of
fibrinogen concentration.
By increasing FDP activity the slope of the obtained lines becomes proportionately
steeper. The constants, which interrelate clotting time, fibrinogen concentration
and FDP activity, are to be derived experimentally. The obtained formula is expressed
also nomographically.
2. Apart from the presence of some very rare anticoagulants, an elongation of thrombin
time observed under strictly specified conditions points to a substantial reduction
of fibrinogen concentration and/or an interplay of fibrinogen degradation products.
If a definite amount of fibrinogen (Fibrinogen sec. Warner Chilcott) is admixed to
a pathological plasma, thrombin time in the latter will decrease in a specifiable
manner. By entering the original and corrected thrombin time values in the reported
nomogram the fibrinogen content and FDP activity of the pathological plasma can be
calculated.
3. The described procedure for fibrinogen and FDP assay is suitable first of all in
acute defibrination syndrome and at the thrombolytic therapy. Its agreement with the
results obtained by immunodiffusion was satisfactory as regards the fibrinogen in
plasmas of different fibrinogen concentration.
