Someone called having high erythrocytes when there is an increase in the level of red blood cells in the body. These blood cells act as carriers of oxygen from the lungs to all body tissues. The numbers that determine normal red blood cell (erythrocyte) levels and other blood examination parameters actually differ from one institution to another. Generally, these levels vary based on age and gender. Normal blood cell counts in adult men range from 700,000 to 5.2 million erythrocytes per microliter (mcL) and women 500,000 to 4.6 million erythrocytes per mcL. Erythrocyte levels can increase if there are conditions where oxygen supply decreases in the body. This triggers the body to make more red blood cells as compensation to maintain oxygen availability. Hemoglobin is a protein in red blood cells that functions to carry oxygen for use in all body tissues. In adult men, normal hemoglobin ranges from 13 to 18 grams per deciliter (dL) and in women ranges from 12 to 16 dL. Hematocrit is...