Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin (MCH) are measurements within a Complete Blood Count (CBC) that provide insight into your red blood cells. This article explains what elevated MCV and MCH values signify and their potential implications. This information is for educational purposes only and should not replace professional medical advice.
Decoding Your Blood Test: What MCV and MCH Represent
MCV measures the average size of your red blood cells. A high MCV indicates that your red blood cells are larger than their typical size, a condition known as macrocytosis. Normal MCV values generally range from 80 to 100 femtoliters (fL), though this can vary slightly between laboratories.
MCH measures the average amount of hemoglobin contained within each red blood cell. Hemoglobin is the protein responsible for carrying oxygen throughout your body. When MCH levels are high, it means your red blood cells carry more hemoglobin than usual. Normal MCH values typically fall between 27 and 33 picograms (pg) per cell.
Understanding Elevated MCV and MCH
Elevated MCV signifies that your red blood cells are larger than average, which can affect their ability to efficiently transport oxygen throughout the body. This condition is known as macrocytosis.
High MCH values frequently correlate with elevated MCV because larger cells naturally have the capacity to hold more hemoglobin. These elevated values are indicators that prompt further medical investigation, rather than being a definitive diagnosis on their own. They suggest that an underlying process is influencing the production or maturation of red blood cells.
Common Reasons for High MCV and MCH
Several factors can lead to elevated MCV and MCH levels:
Nutritional Deficiencies: A lack of vitamin B12 or folate, both essential for DNA synthesis and proper red blood cell maturation, can result in the production of larger, immature red blood cells. This condition is often referred to as megaloblastic anemia.
Liver Disease: Conditions including alcoholic and non-alcoholic fatty liver disease can contribute to high MCV by altering red blood cell membranes. Chronic alcohol consumption can also directly impact bone marrow and interfere with folate metabolism.
Hypothyroidism: An underactive thyroid can sometimes lead to macrocytic anemia. Thyroid hormones play a role in stimulating red blood cell production, and their deficiency can affect this process.
Medications: Certain drugs, such as some chemotherapy agents, antiretrovirals, and anticonvulsants, can disrupt red blood cell development.
Increased Reticulocytes: Immature red blood cells (reticulocytes) are larger than mature red blood cells. Their increased presence, often seen after significant blood loss or in conditions where red blood cells are prematurely destroyed, can temporarily elevate MCV.
Myelodysplastic Syndromes (MDS): These are a group of bone marrow disorders where the bone marrow does not produce enough healthy blood cells, resulting in the formation of abnormally large red blood cells.
What to Do When Your Levels Are High
If your blood test results show elevated MCV and MCH, it is important to consult your doctor. These results require a professional medical evaluation to understand the full clinical picture. Your doctor will consider your medical history, perform a physical examination, and review all your laboratory results.
Additional diagnostic tests are usually necessary to identify the specific cause of the elevation. These might include tests for vitamin B12 and folate levels, liver function tests, or thyroid function tests. In some instances, a bone marrow biopsy may be considered to rule out certain conditions.
Treatment for high MCV and MCH is always directed at addressing the underlying cause. For example, deficiencies in B12 or folate may be managed with supplementation. If liver disease is the cause, its management will be the focus. It is crucial to avoid self-diagnosis or self-treatment based solely on lab results.