From the Guidelines
Elevated MCV and MCH levels are not typically indicative of iron deficiency anemia, as these parameters are usually reduced in iron deficiency, with microcytosis and hypochromia being characteristic findings 1. Instead, these findings may suggest a macrocytic anemia, where red blood cells are larger than normal and contain more hemoglobin. Common causes of macrocytic anemia include:
- Vitamin B12 deficiency
- Folate deficiency
- Alcoholism
- Liver disease
- Hypothyroidism
- Certain medications
- Myelodysplastic syndromes To address this condition, it's essential to identify and treat the underlying cause. Recommended diagnostic tests include:
- Blood tests for vitamin B12 and folate levels
- Liver function tests
- Thyroid function tests
- A complete blood count Treatment depends on the cause but may include:
- Vitamin B12 injections or supplements (typically 1000 mcg daily initially, then maintenance doses)
- Folate supplements (1 mg daily)
- Alcohol cessation
- Medication adjustments Dietary changes to include foods rich in B12 (meat, fish, dairy) and folate (leafy greens, legumes) can help support treatment. These abnormalities should not be ignored as they may indicate serious underlying conditions that could progress if left untreated, and symptoms like fatigue, weakness, and neurological problems may improve with appropriate treatment 1.
From the Research
Elevated MCV and MCH
- Elevated MCV (Mean Corpuscular Volume) and MCH (Mean Corpuscular Hemoglobin) can be indicative of macrocytic anemia, which can be caused by a deficiency in vitamin B12 or folate 2, 3, 4.
- A study found that high MCV and MCH were significantly associated with increased major adverse cardiovascular events (MACEs) in nonanemic patients with acute coronary syndrome 5.
- Another study found that low vitamin B12 status was associated with anemia, macrocytosis, and cognitive impairment, and that high serum folate was associated with anemia and cognitive impairment in seniors with low vitamin B12 status 4.
- Elevated homocysteine levels have been linked to an increased risk of cardiovascular disease and cognitive impairment, and supplementation with vitamins B6, B12, and/or folic acid has been shown to reduce homocysteine levels 6, 5.
Possible Causes
- Vitamin B12 deficiency: can cause macrocytic anemia, which can lead to elevated MCV and MCH 2, 3, 4.
- Folate deficiency: can also cause macrocytic anemia, which can lead to elevated MCV and MCH 2, 4.
- Homocysteine elevation: can be caused by a deficiency in vitamins B6, B12, or folate, and has been linked to an increased risk of cardiovascular disease and cognitive impairment 6, 5.
Associations
- Elevated MCV and MCH have been associated with increased MACEs in nonanemic patients with acute coronary syndrome 5.
- Low vitamin B12 status has been associated with anemia, macrocytosis, and cognitive impairment 4.
- High serum folate has been associated with anemia and cognitive impairment in seniors with low vitamin B12 status 4.
- Homocysteine elevation has been linked to an increased risk of cardiovascular disease and cognitive impairment 6, 5.