Physiologic Basis:
Reticulocytes are young red blood cells that contain cytoplasmic RNA. A reticulocyte count measures how rapidly reticulocytes are produced by the bone marrow and then released into the bloodstream.
Reticulocyte count reflects the erythropoietic activity of the bone marrow and is thus useful in both the diagnosis of anemias and in monitoring bone marrow response to therapy.
Interpretation
Increased in
: Hemolytic anemia, blood loss (before development of iron deficiency), recovery from iron, B12 or folate deficiency, or from drug-induced anemia.
Decreased in
: Iron deficiency anemia, aplastic anemia, anemia of chronic disease, megaloblastic anemia, sideroblastic anemia, pure red cell aplasia, renal disease, bone marrow suppression or infiltration, myelodysplastic syndrome.
Comments
This test is indicated for the evaluation of anemia to distinguish hypoproliferative from hemolytic anemia or blood loss. The old method of measuring reticulocytes (manual staining and counting) has poor reproducibility. It has been replaced by automated methods (eg, flow cytometry-based), which are more precise and provide absolute reticulocyte counts.