From the Guidelines
For a patient with an increasing Red Blood Cell (RBC) count and Mean Corpuscular Volume (MCV), the next steps should include a comprehensive evaluation to determine the underlying cause, starting with a morphologic approach based on MCV to characterize the anemia as microcytic, normocytic, or macrocytic 1. The patient's increasing RBC count and rising MCV suggest a potential macrocytic anemia, which is most commonly caused by vitamin B12 or folate deficiency, and less commonly by alcoholism, myelodysplastic syndromes (MDS), or certain drugs such as hydroxyurea or diphenytoin 1. Key follow-up tests should include:
- Reticulocyte count to assess bone marrow production capacity
- Serum vitamin B12 and folate levels to evaluate for deficiencies
- Liver function tests and hepatitis panel to assess for liver disease
- Thyroid function tests to rule out hypothyroidism
- JAK2 mutation testing to rule out polycythemia vera
- Bone marrow biopsy if MDS is suspected Treatment depends on the underlying cause, but may include vitamin B12 or folate supplementation if deficiencies are identified, and addressing any underlying conditions such as liver disease or hypothyroidism. It is crucial to accurately diagnose the cause of the increasing RBC count and MCV to provide appropriate management and prevent potential complications such as thrombosis or worsening anemia.
From the Research
Increasing Red Blood Cell Count and Mean Corpuscular Volume
- An increase in Red Blood Cell (RBC) count and Mean Corpuscular Volume (MCV) can be indicative of various conditions, including vitamin B12 or folate deficiency 2.
- A high RBC count combined with an increased MCV is not typically associated with thalassemia minor or polycythemia vera with iron deficiency, as these conditions usually present with a low MCV 3.
- Vitamin B12 deficiency can cause an increase in MCV, but it is not a reliable screening parameter for macrocytic anemia associated with this deficiency 4.
- In cases of megaloblastic anemia, treatment with folic acid, vitamin B12, niacin, and vitamin C can lead to a decrease in MCV and an improvement in hematological parameters 5.
Next Steps for Diagnosis and Treatment
- A complete blood cell count (CBC) is a crucial test in diagnosing and managing conditions associated with abnormal RBC counts and MCV 6.
- When confronted with abnormal CBC results, a structured action plan should be followed to determine the underlying cause and appropriate treatment.
- Consultation with a hematologist may be necessary to interpret abnormal CBC results and develop a treatment plan 6.
- Further testing, such as serum vitamin B12 and folic acid levels, may be necessary to determine the underlying cause of the increased RBC count and MCV 4, 5.