Reticulocytes are immature RBC without nuclei. The reticulocyte count provides an estimate of the rate of red cell production. To visualize the reticulum-like RNA and count reticulocytes as a separate group of RBC, a special stain is required. The reticulocytes can be counted manually (at the microscope) and reported as percent per 100 RBC, or by automated counters.
Normal range: 0.3 " “2.3/100 RBCs with automated counters. However, this varies to some extent in the manual methodology. An absolute reticulocyte count or reticulocyte production index is more helpful than the percentage, and this can be calculated from the hematologic data.
Interpretation
Causes of Increased Reticulocytes
Reticulocytosis: Enhanced red cell production most marked in hemolytic anemias or during bone marrow regeneration
Causes of Decreased Reticulocytes
Conditions with inadequate or ineffective hematopoiesis, despite the presence of anemia
Limitations
The manual counts result in great variability, being operator dependent. The automated counters provide better precision. Erythrocyte inclusions, other than the true reticulum, may falsely increase the reticulocyte count. Similar errors occur in sickle cell anemia and sickle/C hemoglobinopathies.