Blood Viscosity

Small amounts of potassium oxalate probably have no effect on the viscosity of the blood and changes hitherto ascribed to it can be attributed either to variation in carbon dioxide content or to sedimentation of the red blood cells. The viscosity of blood when exposed to the air increases rapidly. This change accompanies a loss of carbon dioxide and can be prevented by stoppering the container and agitating until the blood comes into carbon dioxide equilibrium with the air above it, when the viscosity remains constant. It is essential in determining the viscosity of blood that the red cells should be uniformly suspended throughout the plasma. This can be accomplished by rotating 5 to 10 cc. of blood in a separating funnel for 1 minute.