A method for determining the spatiotemporal distribution of activity of a proteolytic enzyme in a heterogeneous system, said method comprising the steps of: • providing an in-vitro system that includes a sample of a test medium, wherein the test medium is one of blood plasma or whole blood comprising a proteolytic enzyme (coagulation factor) or its zymogen, wherein the proteolytic enzyme or its zymogen is distributed in the sample of the test medium; • adding a fluorogenic substrate which is specific for the determined proteolytic enzyme (coagulation factor) into the test medium to obtain a test medium with the fluorogenic substrate; • combining the test medium with the fluorogenic substrate and an activating agent in a cuvette of an in-vitro system, wherein the activating agent induces changes of the spatiotemporal distribution of the proteolytic enzyme (coagulation factor) activity, the fluorogenic substrate is cleaved by the proteolytic enzyme (coagulation factor), and a fluorescent mark is released upon cleavage of the fluorogenic substrate and the activating agent is a tissue factor; • providing and maintaining constant pressure within the in-vitro system, wherein the constant pressure is a pressure elevated compared to the atmospheric pressure; • illuminating the sample of the test medium by means of excitation radiation with the exciting radiation in determined points of time to excite a fluorescence signal of the fluorescent mark; • recording the spatial distribution of the intensity of the fluorescence signal within the in-vitro system in the determined points of time, and obtaining a set of recorded spatial distributions of the intensity of the fluorescence signal; • illuminating the cuvette by means of visible radiation in determined points of time to induce light scattering by the fibrin clot; • recording the spatial distribution of the intensity of the light scattering signal within the in-vitro system in the determined points of time, and obtaining a set of recorded spatial distribution of the intensity of the light scattering signal; • converting the set of the recorded spatial distribution of the intensity of the fluorescence signal into the set of spatial distributions of the activity of the proteolytic coagulation factor in the determined points of time by solving the inverse "reaction-diffusion-convection" equation, wherein the step of converting further includes correction of the distortion of the fluorescence signal caused by light scattering in the fibrin clot at each of the determined points of time. • providing an in-vitro system that includes a sample of a test medium, wherein the test medium is one of blood plasma or whole blood comprising a proteolytic enzyme (coagulation factor) or its zymogen, wherein the proteolytic enzyme or its zymogen is distributed in the sample of the test medium; • adding a fluorogenic substrate which is specific for the determined proteolytic enzyme (coagulation factor) into the test medium to obtain a test medium with the fluorogenic substrate; • combining the test medium with the fluorogenic substrate and an activating agent in a cuvette of an in-vitro system, wherein the activating agent induces changes of the spatiotemporal distribution of the proteolytic enzyme (coagulation factor) activity, the fluorogenic substrate is cleaved by the proteolytic enzyme (coagulation factor), and a fluorescent mark is released upon cleavage of the fluorogenic substrate and the activating agent is a tissue factor; • providing and maintaining constant pressure within the in-vitro system, wherein the constant pressure is a pressure elevated compared to the atmospheric pressure; • illuminating the sample of the test medium by means of excitation radiation with the exciting radiation in determined points of time to excite a fluorescence signal of the fluorescent mark; • recording the spatial distribution of the intensity of the fluorescence signal within the in-vitro system in the determined points of time, and obtaining a set of recorded spatial distributions of the intensity of the fluorescence signal; • illuminating the cuvette by means of visible radiation in determined points of time to induce light scattering by the fibrin clot; • recording the spatial distribution of the intensity of the light scattering signal within the in-vitro system in the determined points of time, and obtaining a set of recorded spatial distribution of the intensity of the light scattering signal; • converting the set of the recorded spatial distribution of the intensity of the fluorescence signal into the set of spatial distributions of the activity of the proteolytic coagulation factor in the determined points of time by solving the inverse "reaction-diffusion-convection" equation, wherein the step of converting further includes correction of the distortion of the fluorescence signal caused by light scattering in the fibrin clot at each of the determined points of time.