Abstract: Apparatus for detecting the viscosity of blood comprises a hypodermic syringe including a transparent hollow tube, a needle secured to one end of the tube and a plunger in the tube for creating a vacuum for extracting a predetermined volume of blood and depositing the blood in the transparent hollow tube for immediately performing internal viscosity measurement without substantial change in temperature and without any chemical change (e.g. exidation) in the blood sample. An apertured weight member within the transparent hollow tube is movable by gravity at a rate which is a function of the viscosity of the blood and indicia means, visible on the side of the transparent tube indicates the rate of movement of the apertured weight member through the predetermined volume of blood as a measure of the viscosity of the blood in the tube.