Management of Low MCH and MCHC (Microcytic Anemia)
The management of microcytic anemia with low Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC) should begin with iron supplementation as first-line therapy, specifically ferrous sulfate 200 mg three times daily for at least three months after anemia correction to replenish iron stores. 1
Diagnostic Approach
- Serum ferritin is the most specific test for iron deficiency, with levels <15 μg/L indicating absent iron stores and <30 μg/L indicating low body iron stores 1
- A ferritin cut-off of 45 μg/L provides optimal sensitivity and specificity for iron deficiency in clinical practice 1
- Transferrin saturation (TSAT) should be evaluated as it is more sensitive for detecting iron deficiency than hemoglobin concentration alone 1
- A low MCV with RDW >14.0% suggests iron deficiency anemia, while a low MCV with RDW ≤14.0% suggests thalassemia minor 1
- In patients with unexplained microcytic anemia with increased TSAT, genetic disorders such as SLC11A2 defects should be considered 2
- For patients with unexplained hypochromic microcytic anemia with low iron binding capacity and increased ferritin, hypotransferrinemia should be considered 2
Treatment Algorithm
Iron Deficiency Anemia (Most Common Cause)
- First-line treatment: Oral iron supplementation with ferrous sulfate 200 mg three times daily for at least three months after correction of anemia 1
- Alternative formulations include ferrous gluconate and ferrous fumarate if ferrous sulfate is not tolerated 1
- Adding ascorbic acid can enhance iron absorption 1
- A good response to iron therapy is defined as a hemoglobin rise ≥10 g/L within a 2-week timeframe, which confirms iron deficiency 1
- For patients who fail to respond to oral iron therapy, consider intravenous (IV) iron if there is malabsorption 1
Genetic Disorders of Iron Metabolism
- For SLC11A2 defects: Treat with oral iron supplementation and/or erythropoietin (EPO) and/or erythrocyte transfusions based on individual needs 2
- For STEAP3 defects: Erythrocyte transfusions in combination with EPO; treat systemic iron loading with chelation 2
- For SLC25A38 defects: Consider hematopoietic stem cell transplantation (HSCT) as the only curative option; symptomatic treatment includes erythrocyte transfusions and chelation therapy 2
- For hypotransferrinemia due to TF defects: Transferrin supplementation by either plasma transfusion or apotransferrin infusion is recommended 2
Monitoring and Follow-up
- Monitor hemoglobin concentration and red cell indices at three-monthly intervals for one year and then after a further year 1
- Provide additional oral iron if hemoglobin or MCV falls below normal 1
- For patients receiving iron therapy, monitor for iron overload, particularly in genetic disorders 2
- In cases of SLC11A2 defects, monitor iron status to detect toxic iron loading early; MRI of the liver should be considered since normal serum ferritin does not exclude liver iron loading 2
- In case of systemic iron loading, phlebotomies are recommended; if not tolerated due to decreasing hemoglobin, chelation therapy should be considered 2
Special Considerations
- Genetic testing should be considered in patients with refractory microcytic anemia despite adequate iron supplementation 2
- Family screening may be recommended for patients diagnosed with genetic disorders affecting iron metabolism 2
- In children with severe unexplained microcytic sideroblastic anemia, defects in SLC25A38 should be considered 2
- In male patients presenting with mild microcytic anemia and ataxia, defects in ABCB7 should be considered 2
- Avoid overlooking combined deficiencies, such as iron deficiency coexisting with B12 or folate deficiency 1
By following this algorithmic approach, clinicians can effectively manage patients with low MCH and MCHC, ensuring proper diagnosis and treatment to improve morbidity, mortality, and quality of life outcomes.