Abstract: A process for detecting parasites which are found in the blood of a host. A sample of blood is drawn into a capillary tube which contains a generally cylindrical mass having a specific gravity such that it will float in one of the cell layers when the sample is separated by centrifugation. The specific gravity of the mass is selected so as to cause the cylindrical mass to combine with the bore wall of the capillary tube to form a thin annular space in the capillary tube into which the parasites will be crowded, thus increasing the concentration of parasites in a restricted area of the centrifuged blood sample and rendering the parasites highly visible. A stain may be used to differentially color the parasites. One specific parasite which can be detected in this manner quickly and inexpensively is heartworm.

Abstract: A method whereby separation of red cells from white cells in a centrifuged blood sample is improved. An effective amount of potassium oxalate is added to the blood sample to increase the density of the red cells. The blood sample is then warmed to minimize the increase in density of the white cells which otherwise occurs in certain cases.

Abstract: A technique for generally determining the volume of a layer of a constituent material in a centrifugally separated mixture of material. A centrifuge tube is used to hold the material mixture and an appropriately shaped body is disposed in the tube in the zone occupied by the constituent material whose volume is to be measured. The body reduces the available volume within the tube which may be occupied by the constituent material, and thus expands the axial extent of the constituent material to make visual measurement of the constituent material more accurate.