Cold atmospheric plasma (CAP) is produced by ionizing a chosen gas, thereby creating charged and reactive species. The reactive species generated are capable of inducing a range of biomedically relevant interactions including blood coagulation. However, the underlying biochemical processes of plasma-assisted blood coagulation are largely unknown, and data quantifying blood clot formation or the impact of system parameters on the intensity of the blood clot are scarce. In this study, blood coagulation was quantified by measuring hemoglobin absorbance. System parameters of the kINPen plasma jet were investigated and compared, including treatment time, distance from the plasma source and gas flow rate. These investigations were combined with optical emission spectroscopy to associate the species generated in the plasma effluent with the effect on coagulation efficiency. In this study, we have proposed a method to quantitatively assess plasma-induced blood coagulation to directly compare the clotting capabilities of other plasma systems and to explicate the mechanism of plasma-assisted blood coagulation.