Last reviewed 08/2021

Reticulocytes normally account for 0.8 - 2.0% of the circulating red blood cells. They are juvenile red cells produced by erythropoiesis which spend about 24 hours in the marrow before entering the peripheral circulation. They contain some nuclear material - remnants of RNA - which appears faintly blue - basophilic - in conventionally stained blood smears.

Reticulocytes persist for a few days in the circulation before forming the slightly smaller, mature red cell.