Reticulocytes account for approximately 0.5% to 2.5% of the total red blood cells in healthy adults and 2% to 6% in infants, but in reticulocytosis, this percentage rises.

[1] Reticulocytes are produced in the bone marrow and then released into the bloodstream, where they mature into fully developed red blood cells between 1-2 days.

[2] Reticulocytosis often reflects the body’s response to conditions rather than an independent disease process and can arise from a variety of causes such as blood loss or anemia.

When red blood cells are destroyed or lost, tissues experience low oxygen levels causing the kidneys to release the hormone erythropoietin.

[4] Reticulocytosis provides strong suspicion of hemolysis when present along with many other markers like elevations in lactate dehydrogenase and unconjugated bilirubin or a decrease in haptoglobin.