Abstract: A sensor device (10) and a method for measuring a viscosity of a sample of a liquid. The sensor features a chamber (12) for receiving the sample of the liquid, two electrodes (18) disposed either on the surfaces of the chamber, but possibly isolated from contacting the sample, or electrodes located externally to the chamber, and a capacitance measuring circuit (25). The sensor is used by connecting to a measurer for determining a capacitance on the electrodes, such that the capacitance directly reflects a volume occupied by the sample of the liquid. Preferably, the liquid is blood and the capacitance is used to determine the clotting time of the blood. Also preferably, a cover for the chamber is provided with at least one aperture, which more preferably is a mesh. Alternatively, an electrical property such as the amplitude of current passed through the sample is used to determine clotting time. Also preferably, the time period required for the maximum capacitance to be reached could be measured.