From the Guidelines
The primary distinction between Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC) lies in their measurement of hemoglobin in red blood cells, with MCH quantifying the average amount of hemoglobin per cell and MCHC measuring the average concentration of hemoglobin within a cell. When interpreting a Complete Blood Count (CBC), it's crucial to understand the differences between these two parameters to accurately diagnose and manage various types of anemias.
- MCH is expressed in picograms (pg) and reflects the total amount of hemoglobin in a red blood cell, making it a useful marker for conditions like iron deficiency, where it is often reduced 1.
- MCHC, on the other hand, is expressed as a percentage or in grams per deciliter (g/dL) and indicates how densely packed the hemoglobin is within the red blood cell, aiding in the identification of conditions such as spherocytosis or hypochromic anemias. The utility of MCH and MCHC in diagnosing anemias is complemented by other markers, including serum ferritin levels, which are highly specific for iron deficiency, especially when levels are below 15 μg/L 1. In clinical practice, both MCH and MCHC are essential for a comprehensive assessment of red blood cell health and function, allowing for more precise diagnoses and targeted treatments for various anemic conditions. Key points to consider include:
- The sensitivity and specificity of MCH and MCHC in the context of different anemias and conditions affecting red blood cells.
- The role of serum ferritin and other iron studies in confirming iron deficiency, particularly in cases where MCH and MCHC values are altered 1.
- The importance of considering the clinical context, including the presence of chronic diseases or other conditions that may affect the interpretation of MCH and MCHC values.
From the Research
Difference between MCH and MCHC
- MCH (Mean Corpuscular Hemoglobin) and MCHC (Mean Corpuscular Hemoglobin Concentration) are two important parameters in a Complete Blood Count (CBC) test.
- MCH measures the average amount of hemoglobin in a single red blood cell, while MCHC measures the average concentration of hemoglobin in a given volume of red blood cells 2.
- In other words, MCH measures the total amount of hemoglobin in a red blood cell, whereas MCHC measures the percentage of hemoglobin in a red blood cell.
Clinical Significance
- Both MCH and MCHC are used to diagnose and monitor various blood disorders, such as anemia and thalassemia 3, 4.
- A low MCH value may indicate iron deficiency anemia, while a low MCHC value may indicate thalassemia or other hemoglobinopathies 2, 4.
- On the other hand, a high MCH value may indicate a condition called macrocytosis, where red blood cells are larger than normal, while a high MCHC value may indicate a condition called polycythemia, where there is an excess of red blood cells 5, 6.
Diagnostic Criteria
- According to a study published in 2024, a MCV value of ≤73.8 fl and a MCH value of ≤21.9 pg may be a clue of diagnosis for beta thalassemia trait (BTT) rather than E-trait with >90% sensitivity and >80% specificity 4.
- Another study published in 2012 found that MCH and MCV are useful markers in predicting iron deficiency anemia, with a best predictive cut-off value of 24 Pg for MCH and 76 fl for MCV 2.