From the Guidelines
Slightly elevated MCV and MCH values are indicative of macrocytosis, which may suggest vitamin B12 or folate deficiency, and warrant further evaluation with additional tests such as vitamin B12 and folate levels, as recommended by the European Consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases 1. The implications of slightly elevated Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin (MCH) are significant, as they can indicate underlying conditions that affect red blood cell production.
- Macrocytosis, characterized by larger than normal red blood cells with more hemoglobin than average, can be caused by various factors, including vitamin B12 or folate deficiency, liver disease, alcoholism, certain medications, hypothyroidism, or myelodysplastic syndromes.
- According to the European Consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases 1, macrocytosis may indicate B12 or folate deficiency, and the MCV and MCH are useful variables in detecting iron deficiency in the presence of inflammation.
- A comprehensive workup, including complete blood count with MCV, reticulocytes, serum ferritin, transferrin saturation, and CRP, is essential in evaluating slightly elevated MCV and MCH values, as recommended by the European Consensus 1.
- Further testing, such as vitamin B12 and folate levels, liver function tests, thyroid function tests, and possibly a peripheral blood smear, may be necessary to determine the underlying cause of macrocytosis.
- Treatment depends on the underlying cause, and mildly elevated values should not be ignored, as they could indicate an underlying condition that needs attention, such as vitamin supplementation for deficiencies or addressing alcohol consumption if relevant.
From the Research
Implications of Slightly Elevated MCV and MCH
- Slightly elevated Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin (MCH) can be indicative of macrocytic anemia, which can be caused by various factors such as vitamin B12 or folate deficiency, myelodysplastic syndrome, liver dysfunction, alcoholism, hypothyroidism, and certain drugs 2.
- A study found that low MCH was superior to low MCV in predicting low serum ferritin values, and that vitamin B12 or folate deficiency could not be predicted from the MCV alone 3.
- Another study found that patients with both vitamin B12 and iron deficiencies had a significantly higher frequency of Hb deficiency, abnormally elevated blood homocysteine level, and serum GPCA positivity than healthy control subjects, and that approximately 73% of patients with both vitamin B12 and iron deficiencies had normal MCV 4.
- Elevated MCV can also be a sign of underlying vitamin B12 or folic acid deficiency, and estimation of serum vitamin B12 and folate level are advisable in children with macrocytic anemia prior to starting treatment 5.
- Changes in MCV during cytotoxic treatment of cancer can be a risk factor for secondary leukemia, and monitoring MCV changes during therapy can help identify patients at high risk 6.