<P> The buffy coat is usually whitish in color, but is sometimes green if the blood sample contains large amounts of neutrophils, which are high in green - colored myeloperoxidase . The layer beneath the buffy coat contains granulocytes and red blood cells . </P> <Ul> <Li> Quantitative buffy coat (QBC) is a laboratory test to detect infection with malaria or other blood parasites . The blood is taken in a QBC capillary tube which is coated with acridine orange (a fluorescent dye) and centrifuged; the fluorescing parasites can then be observed under ultraviolet light at the interface between red blood cells and buffy coat . This test is more sensitive than the conventional thick smear and in> 90% of cases the species of parasite can also be identified . </Li> <Li> In cases of extremely low white blood cell count, it may be difficult to perform a manual differential of the various types of white cells, and it may be virtually impossible to obtain an automated differential . In such cases the medical technologist may obtain a buffy coat, from which a blood smear is made . This smear contains a much higher number of white blood cells than whole blood . </Li> </Ul> <Li> Quantitative buffy coat (QBC) is a laboratory test to detect infection with malaria or other blood parasites . The blood is taken in a QBC capillary tube which is coated with acridine orange (a fluorescent dye) and centrifuged; the fluorescing parasites can then be observed under ultraviolet light at the interface between red blood cells and buffy coat . This test is more sensitive than the conventional thick smear and in> 90% of cases the species of parasite can also be identified . </Li> <Li> In cases of extremely low white blood cell count, it may be difficult to perform a manual differential of the various types of white cells, and it may be virtually impossible to obtain an automated differential . In such cases the medical technologist may obtain a buffy coat, from which a blood smear is made . This smear contains a much higher number of white blood cells than whole blood . </Li>

What component of blood does each section of the hematocrit tube represent