From the Guidelines
Management for a patient with slightly elevated RBC count and high MCV should begin with identifying the underlying cause through additional testing, prioritizing vitamin B12 and folate levels, as indicated by the most recent and highest quality study 1. The initial workup should include:
- Vitamin B12 and folate levels to assess for deficiency, which can cause macrocytosis
- Liver function tests to evaluate for liver disease, which can also lead to macrocytosis
- Thyroid function tests to check for hypothyroidism, a potential cause of macrocytic anemia
- Alcohol use assessment, as alcohol abuse can lead to macrocytosis
For B12 deficiency, treatment involves cyanocobalamin 1000 mcg intramuscularly daily for one week, then weekly for one month, followed by monthly injections or oral supplementation of 1000-2000 mcg daily, as supported by previous studies 1. Folate deficiency requires supplementation with 1-5 mg daily for 1-4 months. If alcohol-related, cessation counseling and support are essential. Liver disease may require specific management based on etiology. Hypothyroidism should be treated with levothyroxine starting at 25-50 mcg daily, adjusted based on TSH levels. Myelodysplastic syndromes may require hematology referral. During evaluation, patients should be monitored for anemia symptoms despite elevated RBC count, as macrocytic RBCs may be less efficient at oxygen delivery. The combination of elevated RBC count with high MCV is unusual and suggests a compensatory mechanism or mixed disorder, making diagnostic workup particularly important, as noted in the guidelines for managing iron deficiency anemia 1.
From the Research
Patient's Blood Test Results
The patient's blood test results show a slightly elevated RBC count of 4.54 x10E6/uL, which is above the normal range of 3.77-5.28 x10E6/uL. The MCV value is also high at 98 fL, exceeding the normal range of 79-97 fL.
Interpretation of Results
According to the study by 2, spurious results on haematology analysers may be observed in several instances, including lipids, agglutinins, cryoglobulins, and elevated WBC counts. However, in this case, the patient's WBC count is within the normal range. The high MCV value may indicate macrocytic anemia, which can be caused by various factors, including vitamin B12 or folate deficiency.
Appropriate Management
The study by 3 provides practical diagnostic algorithms for frequently encountered conditions associated with CBC abnormalities, including anemia, thrombocytopenia, leukopenia, polycythemia, thrombocytosis, and leukocytosis. For a patient with a slightly elevated RBC count and high MCV value, the following steps may be taken:
- Further investigation to determine the cause of the macrocytic anemia, such as vitamin B12 or folate deficiency
- Consideration of other potential causes of elevated RBC count, such as dehydration or polycythemia vera
- Monitoring of the patient's blood test results to ensure that the values return to normal range
Key Considerations
The study by 4 highlights the importance of screening for anemia in pregnancy, and the use of MCV/RBC count ratio to discriminate between iron deficiency anemia and beta-thalassaemia trait, as reported in the study by 5. However, in this case, the patient's MCV value is high, which may indicate macrocytic anemia rather than iron deficiency anemia. The study by 6 suggests that reticulocyte hemoglobin may be a useful marker of bone marrow iron store in iron deficiency anemia, but its relevance to this patient's condition is unclear.
Possible Next Steps
Based on the patient's blood test results and medical history, the following possible next steps may be considered:
- Further testing to determine the cause of the macrocytic anemia, such as vitamin B12 or folate deficiency
- Monitoring of the patient's blood test results to ensure that the values return to normal range
- Consideration of other potential causes of elevated RBC count, such as dehydration or polycythemia vera
- Consultation with a hematologist or other specialist to determine the best course of action for the patient's specific condition.