From the Guidelines
Increased reticulocytes in the bloodstream primarily occur when the bone marrow increases red blood cell production in response to anemia or blood loss. Common causes of increased reticulocytes include:
- Acute or chronic bleeding, such as from trauma, gastrointestinal bleeding, or heavy menstruation
- Hemolytic anemias, where red blood cells are destroyed prematurely, including autoimmune hemolytic anemia, sickle cell disease, and thalassemias
- Recovery from iron, vitamin B12, or folate deficiency after supplementation begins
- Response to certain medications like erythropoietin therapy
- High altitude exposure, which stimulates red blood cell production due to lower oxygen levels
- Recovery from bone marrow suppression after chemotherapy or radiation, as seen in patients with cancer 1 The reticulocyte count serves as an important diagnostic indicator of bone marrow function and its response to anemia, with normal values typically ranging from 0.5-2.5% of total red blood cells, as noted in the evaluation of anemia in patients with chronic kidney disease 1. A high reticulocyte count generally indicates that the bone marrow is functioning properly and responding appropriately to increased demand for red blood cells, while low counts in the presence of anemia suggest bone marrow dysfunction or nutritional deficiencies, such as iron deficiency, which can be evaluated through serum iron and transferrin saturation levels 1. In patients with inflammatory bowel diseases, increased reticulocytes can also be seen in response to anemia of chronic disease, which may involve a combination of iron deficiency and anemia of chronic disease 1. Additionally, certain genetic disorders, such as pyruvate kinase deficiency, can also lead to increased reticulocytes due to hemolytic anemia 1. Overall, the causes of increased reticulocytes are diverse and require a comprehensive evaluation to determine the underlying etiology and guide appropriate management.
From the Research
Causes of Increased Reticulocytes
The causes of increased reticulocytes can be attributed to various factors, including:
- Hemolytic anemia, which is characterized by the premature destruction of red blood cells, leading to an increase in reticulocyte production 2
- Iron deficiency anemia, which can cause an increase in reticulocyte count due to the bone marrow's attempt to compensate for the lack of iron 3, 4
- Increased erythropoietic stimulation, which can occur in response to anemia, blood loss, or other conditions that require increased red blood cell production 5
- Hematological disorders, such as polycythaemia vera, dyserythropoietic syndromes, acute myeloid leukemia, and acute lymphoid leukemia, which can affect reticulocyte counts and hemoglobin parameters 5
Reticulocyte Parameters
Reticulocyte parameters, such as reticulocyte hemoglobin content (CHr) and mean corpuscular reticulocyte volume (MCVr), can provide valuable information about the causes of anemia and the effectiveness of therapy 4, 6
- CHr can help identify iron deficiency anemia and track the success of therapy 4, 6
- MCVr can help distinguish between different types of anemia and monitor the response to treatment 4
Clinical Significance
Increased reticulocytes can be a sign of underlying hematological disorders or other conditions that require medical attention 2, 5
- Accurate diagnosis and treatment of the underlying cause of increased reticulocytes are crucial to prevent complications and improve patient outcomes 6