The clinical and diagnostic value of counting red blood cells in the Goryaev chamber. A decrease in the number of red blood cells is called erythrocytopenia or erythropenia and is one of the main laboratory criteria for anemia. However, the degree of erythrocytopenia varies widely in different forms of anemia. So, with the most common disease - iron deficiency anemia due to chronic blood loss - the number of red blood cells may be normal or slightly reduced. With acute blood loss, B12-deficient anemia (in the stage of relapse), hypoplastic anemia, hemolytic anemia (during a crisis), the number of red blood cells in the blood can significantly decrease.
An increase in the number of red blood cells in the blood - erythrocytosis - can be caused by many reasons. Significant erythrocytosis is one of the important laboratory symptoms of erythremia (blood cancer).