Reticulocyte is the intergradation from late-young red blood cells to mature cells. Because there are still basophilic RNA in reticulocyte plasma, after stained, light or dark blue reticulations will be visible under the microscope. BaSO Reticulocyte Stain is mainly used for in vivo reticulocyte staining. The background of this stain is bright and very clear, and the result interpretation will not be affected due to excessive staining time. Instead, when performing an extended staining period, the background becomes brighter and clearer, which is better for microscopic examination. Therefore, it is currently a preferred staining reagent for reticulocyte stain. Baso Reticulocyte Stain can be used as hemoglobin H inclusion bodies staining reagent as well.