A microfluid thromboelastometry instrument for analyzing a viscosity of a sample fluid is provided. The microfluid thromboelastometry instrument includes a cartridge for measuring changes in the viscosity of a fluid, the cartridge includes an inlet and an outlet, wherein a flow of the fluid is provided through the cartridge between the inlet and the outlet. The cartridge includes at least one micro-pillar having at least one first position, the at least one micro-pillar is capable of bending with a fluid flow, and an amount of bending increases as the viscosity of the fluid increasing and restores to the at least one first position of the at least one micro-pillars in response to viscosity decrease of the fluid. The micro-pillar is fixed to the surface of the cartridge from the root and has a free distal extremity. A displacement of the micro-pillar distal extremity relative to the micro-pillar root is monitored.