Reticulocytes-Mother of Erythrocytes

Reticulocytes are immature red blood cells (RBCs) that is seen in the bone marrow after through nuclear extrusion from the orthochromatic normoblasts. They are released into the peripheral blood as mature RBCs, after completion of maturation in the bone marrow. The reticulocyte count reflects the erythropoietic activity of the bone marrow, the rate of reticulocyte delivery from the bone marrow into the peripheral blood, and the rate of reticulocyte maturation. Reticulocyte enumeration is also of value in monitoring bone marrow regenerative activity after chemotherapy or bone marrow transplantation. Manual counting of reticulocytes by light microscopy with supravital dyes for RNA remains the standard method of reticulocyte enumeration. However, automated methods of reticulocyte enumeration developed during the past decade are much more accurate, precise, and cost-effective than manual counting, and are increasingly being performed in the clinical laboratory. The differentiation of the reticulocyte is based on the presence of RNA. The newer techniques provide a variety of reticulocyte related parameters, such as the reticulocyte maturation index and immature reticulocyte fraction, which are not available with light microscopy. These new parameters are under evaluation in the clinical diagnosis and monitoring of hematological disorders.