Mean Corpuscular Hemoglobin

Mean Corpuscular Hemoglobin (MCH) is a red blood cell index that offers insights into the average hemoglobin content within these cells. 

Hemoglobin, often likened to the bloodstream's delivery truck, facilitates oxygen transport from the lungs to various bodily tissues, ensuring optimal function and vitality. 

Mean Corpuscular Hemoglobin (MCH) represents the average amount of hemoglobin contained in a single red blood cell. It plays a crucial role in diagnosing and monitoring conditions related to red blood cell health, such as anemia or polycythemia. 

While MCH focuses on the average hemoglobin content per red blood cell, Mean Corpuscular Hemoglobin Concentration (MCHC) measures the concentration of hemoglobin in a given volume of red blood cells, providing insight into the hemoglobin's density within these cells.

In this comprehensive exploration of MCH, we will delve into its significance within blood tests, the testing procedure, interpretation nuances, and the clinical implications of deviations from normal levels. 

By understanding what low or high MCH levels may signify, individuals and healthcare providers can navigate potential health concerns more effectively, paving the way for informed diagnoses and tailored treatment strategies.

What is Mean Corpuscular Hemoglobin (MCH)?

Definition of MCH

Mean Corpuscular Hemoglobin (MCH) is a crucial parameter measured in blood tests, reflecting the average concentration of hemoglobin within a single red blood cell (RBC).  Technically, it is a measurement of the mass of hemoglobin inside a RBC.  It is not measured directly, but instead is calculated.  

As one of the red blood cell indices, it is used to understand the nature of various anemias.  

Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) are the RBC indices used to define the size (MCV) and hemoglobin content (MCH, MCHC) of red blood cells.  [15.]

Mean Corpuscular Hemoglobin (MCH) quantifies the amount of hemoglobin per red blood cell, with normal values being approximately 29 ± 2 picograms (pg) per cell. It provides an indication of the average hemoglobin content in each red blood cell, which is crucial for diagnosing and classifying anemias.  [15.]

MCH is related to Mean Corpuscular Hemoglobin Concentration (MCHC), which indicates the amount of hemoglobin per unit volume of red blood cells, but while MCH focuses on the average hemoglobin per cell, MCHC relates the hemoglobin content to the cell volume​​.

This metric provides valuable insights into red blood cell health and oxygen-carrying capacity.

Importance in Blood Analysis: What Does MCH in Blood Tests Tell Us?

MCH in blood tests serves as a pivotal marker for evaluating the quality and functionality of red blood cells.  Deviations from the normal MCH range can indicate various health conditions ranging from anemia to hemolytic disorders, providing crucial diagnostic clues for healthcare providers.

An increase or decrease in MCH alone is not always indicative of an underlying disease or condition; results should be interpreted within the context of the individual’s full health picture.  

MCH’s Role in the Complete Blood Count (CBC) Test

The relationship between Mean Corpuscular Hemoglobin Concentration (MCHC), Mean Corpuscular Hemoglobin (MCH), and Mean Corpuscular Volume (MCV) lies at the core of understanding red blood cell characteristics. 

MCHC represents the concentration of hemoglobin within each red blood cell, providing insight into their hemoglobin content relative to cell volume. On the other hand, MCH measures the average amount of hemoglobin in each red blood cell without considering cell volume. 

Meanwhile, MCV reflects the average volume of red blood cells. 

The relationship between hemoglobin concentration and cell size helps identify various types of anemia, hemoglobinopathies, and other hematological disorders. 

The Mean Corpuscular Hemoglobin (MCH) test is instrumental in diagnosing and classifying anemias, as variations in MCH values can indicate different types of anemia. For example, a low MCH value may suggest iron deficiency anemia, while a high MCH value could indicate macrocytic anemia. 

How Does MCH Relate to Red Blood Cell Health or Disease?

Erythropoiesis, the process of red blood cell (RBC) formation, begins in the bone marrow with the differentiation of hematopoietic stem cells into erythroid progenitor cells. These progenitor cells then mature into erythroblasts, which subsequently develop into reticulocytes and finally into mature RBCs. 

Various factors influence erythropoiesis, including erythropoietin levels, iron availability, and the presence of other essential nutrients such as vitamin B12 and folate.

Deviation from normal erythropoiesis can lead to alterations in Mean Corpuscular Hemoglobin Concentration (MCHC), Mean Corpuscular Hemoglobin (MCH), and Mean Corpuscular Volume (MCV). 

For instance, inadequate iron availability or impaired hemoglobin synthesis during erythropoiesis can result in microcytic, hypochromic RBCs, characterized by decreased MCV, MCH and MCHC. This is commonly seen in iron deficiency anemia.

Conversely, conditions such as vitamin B12 or folate deficiency can lead to macrocytic RBCs with increased MCV, often associated with higher MCH values. These cells may contain normal or decreased MCHC levels.

In contrast, in hemolytic disorders or conditions where RBCs are prematurely destroyed, such as hereditary spherocytosis, there may be an increase in MCH and MCHC due to the release of hemoglobin from lysed RBCs, leading to hyperchromic RBCs.  [5.]

Overall, deviations from normal erythropoiesis can result in changes in MCHC, MCH, and MCV values, providing valuable diagnostic clues for healthcare professionals in identifying and managing various hematological disorders. 

Testing Options and Procedure

MCH is tested as part of a complete blood count (CBC) which requires a blood draw.  Fasting is not required for this test.  

Procedure Overview

The procedure for measuring Mean Corpuscular Hemoglobin (MCH) involves automated analysis as part of a complete blood count (CBC) test. MCH is calculated by dividing the hemoglobin concentration by the hematocrit (the proportion of blood that is composed of red blood cells) and multiplying by 100. The results are reported in grams per deciliter (g/dL).

Interpretation of MCH Test Results

Normal Reference Range

Typical MCH reference ranges include: [12.]

Adult/elderly/child: 27-31 pg

Newborn: 32-34 pg

It is important to check with the individual lab company used.  

Clinical Significance of Low MCH Levels (Hypochromia)

Low MCH, or hypochromia, refers to a condition where the concentration of hemoglobin within red blood cells is lower than the normal range, indicating reduced oxygen-carrying capacity. 

Low MCH is called hypochromia because it describes a condition where red blood cells appear paler than usual under a microscope due to a decrease in the concentration of hemoglobin within the cells. 

Causes of Low MCH  [15.]

• Iron deficiency anemia
• Thalassemia
• Inflammatory conditions (e.g., rheumatoid arthritis)
• Chronic diseases (e.g., chronic inflammatory disorders, cancer)
• Lead poisoning
• Chronic blood loss (e.g., excessive menstruation, gastrointestinal bleeding)
• Splenectomy [3.]

Symptoms of Low MCH

Symptoms associated with low MCH levels often reflect the reduced oxygen-carrying capacity of the blood and may include fatigue, weakness, shortness of breath, pale skin, and dizziness. 

Clinical Significance of High MCH Levels (Hyperchromia)

High MCH is called hyperchromia because it refers to a condition where red blood cells appear darker than normal under a microscope due to an increased concentration of hemoglobin within the cells, resulting in a higher-than-usual color intensity.  [4.]

Causes of High MCH  

• Vitamin B12 and/or folate deficiency  [9.]
• Hereditary spherocytosis
• Autoimmune hemolytic anemia
• Dehydration
• Burns
• Hyperthyroidism  [6.]
• Hemoglobinopathies (e.g., sickle cell disease)
• Hemolysis (abnormal breakdown of red blood cells)
• Hyponatremia  [4.] 
• Hemochromatosis (excessive iron absorption leading to iron overload) [2.]
• Polycythemia vera (bone marrow disorder leading to excessive production of red blood cells)
• Liver disease
• Congenital dyserythropoietic anemia
• Certain medications (Methyldopa therapy, antihypertensive medication associated with hemolytic anemia; erythropoietin)

Symptoms of High MCH

Symptoms of hyperchromia-related conditions may include jaundice, dark urine, abdominal pain, and an enlarged spleen. 

Diet and Lifestyle Factors for Red Blood Cell Health

As a vital marker of red blood cell health, various diet and lifestyle factors may support healthy MCH levels.

Dietary Factors

Iron-rich foods: Include sources such as lean meats, poultry, fish, legumes, tofu, nuts, seeds, and fortified cereals to support iron absorption and hemoglobin synthesis.

Vitamin B12 sources: Consume foods like fish, shellfish, meat, poultry, eggs, dairy products, and fortified plant-based foods to support erythropoiesis and red blood cell production.  [11.]

Folate-rich foods: Incorporate leafy green vegetables, legumes, citrus fruits, fortified grains, and liver into your diet to support DNA synthesis and red blood cell maturation.  [9.]

Vitamin C-rich foods: Pair iron-rich foods with sources of vitamin C, such as citrus fruits, strawberries, kiwi, bell peppers, and broccoli, to enhance iron absorption.  [8.]

Hydration: Drink an adequate amount of water daily to maintain proper blood volume and circulation, which supports red blood cell function.

Avoid excessive alcohol consumption: Excessive alcohol intake can impair red blood cell production and lead to anemia.  [1.]

Balanced diet: Consume a well-balanced diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats to provide essential nutrients for overall health and red blood cell production.

Lifestyle Factors

Regular exercise: Engage in moderate-intensity aerobic exercise and strength training to stimulate red blood cell production and improve oxygen delivery to tissues.  [16.]

Anti-inflammatory lifestyle: Avoid dietary and lifestyle habits including processed food, sleep deprivation, smoking or excessive alcohol, and excessive stress as inflammation damages red blood cell health and function.  [10.]

Maintain a healthy weight: Aim for a healthy body weight through balanced nutrition and regular physical activity to support optimal blood circulation and red blood cell production.

Avoid smoking: Smoking can impair oxygen delivery to tissues and damage blood vessels, negatively affecting red blood cell health.  [17 .]

Regular medical check-ups: Visit your healthcare provider regularly for routine screenings and assessments to detect and address any underlying health conditions that may affect red blood cell health.

Testing Options for MCH Levels

Click here for a list of testing options to assess MCH as part of a CBC.