Counting Blood Cells

The hematocrit is the volume percentage of red blood cells (RBCs) in blood, measured as part of a blood test. The measurement depends on the number and size of red blood cells.It is normally 40.7–50.3% for males and 36.1–44.3% for females.White blood cells and platelet counts may also be measured.The purpose of red blood cells is to transfer oxygen from the lungs to body tissues. Hematocrit levels that are too high or too low can indicate a blood disorder, dehydration, or other medical conditions.Optical methods such as spectrophotometry or cells can be counted using a haemocytometer, a glass microscope slide used for manually counting cells in a sample.To help count the cells methodically and accurately, the haemocytometer contains a grid of varying sized squares and perpendicular lines.To calculate the number of cells per mm³, you must know the volume of the counting chamber e.g. 0.1mm³.