A blood test showing a high Mean Corpuscular Hemoglobin (MCH) indicates red blood cell health, specifically the amount of hemoglobin they contain. Hemoglobin is a protein in red blood cells that carries oxygen throughout the body. A high MCH result is not a diagnosis itself, but it often warrants further investigation into overall blood health.
Understanding Mean Corpuscular Hemoglobin (MCH)
MCH measures the average quantity of hemoglobin in each red blood cell. This measurement is typically reported in picograms (pg) per cell as part of a complete blood count (CBC) test. Hemoglobin binds to oxygen in the lungs and releases it to tissues throughout the body, providing energy for bodily functions.
The normal MCH range for adults generally falls between 27 and 33 pg per cell, though this can vary slightly between laboratories. MCH is one of several “red blood cell indices” in a CBC, which provide a detailed look at red blood cell characteristics. These indices help healthcare providers assess red blood cell health and aid in diagnosing various conditions.
Interpreting an Elevated MCH Result
An elevated MCH result indicates red blood cells are, on average, carrying more hemoglobin than usual. This often means the red blood cells are larger than their typical size, a characteristic known as macrocytosis. When accompanied by a low red blood cell count, this is referred to as macrocytic anemia.
Macrocytic anemia signifies the body produces abnormally large red blood cells. These larger cells may contain more hemoglobin per cell, leading to the elevated MCH value. Understanding the red blood cells’ characteristics helps identify the underlying causes.
Key Conditions Associated with High MCH
Several medical conditions and factors can lead to an elevated MCH, primarily by causing red blood cells to become larger. A common reason for high MCH is a deficiency in vitamin B12 or folate (vitamin B9). These B vitamins are crucial for proper DNA synthesis during red blood cell production, and their deficiency leads to larger, immature red blood cells.
Liver diseases, including alcoholic liver disease and cirrhosis, can also cause elevated MCH. Liver dysfunction can lead to larger red blood cells by affecting membrane composition. Excessive alcohol consumption can also directly contribute to macrocytosis and a high MCH, even without significant liver damage.
Hypothyroidism, an underactive thyroid gland, is another condition associated with elevated MCH levels. Certain medications, such as some chemotherapy drugs, antiepileptic drugs, and estrogen-containing medications, can interfere with red blood cell development or nutrient absorption, leading to larger cells. Rarer conditions, like myelodysplastic syndromes, where the bone marrow produces abnormal blood cells, can also manifest with high MCH values.
What to Do After a High MCH Result
A high MCH result is a laboratory finding, not a definitive diagnosis; it requires further medical evaluation. Consult a healthcare professional to discuss the result in the context of your overall health, symptoms, and other blood test findings. Self-diagnosing or self-treating based solely on an MCH value is not recommended.
Your doctor may order additional tests to identify the underlying cause of the elevated MCH. These might include specific blood tests for vitamin B12 and folate levels, liver function tests, or a thyroid panel. In some cases, a reticulocyte count, which measures immature red blood cells, or a bone marrow biopsy may be considered to investigate red blood cell production. Treatment for an elevated MCH focuses on addressing the identified underlying condition rather than directly targeting the MCH value. For example, if a vitamin deficiency is found, supplementation may be prescribed.