High reticulocytes indicate that the bone marrow erythrocyte lineage is proliferating, suggesting that there may be iron deficiency anemia and other related diseases. Reticulocytes, the red blood cell stage after the denucleation of late juvenile erythrocytes, are named after the light blue or dark blue reticulocytes after staining with new methylene blue due to the residual alkaliphilic substances such as ribosomes in the cytoplasm. Normal values range from 0.5%-1.5% in adults and children, and 0.03%-0.06% in newborns. An increase in reticulocytes usually indicates an exuberant proliferation of the bone marrow erythrocyte lineage, suggesting that the patient may be suffering from iron-deficiency anemia, hemolytic anemia, acute blood loss, megaloblastic anemia, and other related patients, due to the body’s loss of blood or anemia, and therefore through a negative feedback mechanism to make the reticulocytes increase. If laboratory tests indicate high reticulocytes, it is recommended to go to a regular hospital to avoid delay.