Mean cell haemoglobin (MCH) is the average amount of haemoglobin found in red blood cells. Although they are similar, MCH is different from mean cell haemoglobin concentration (MCHC). They both reflect the health of red blood cells but MCH measures the average amount of haemoglobin in each red blood cell, whereas MCHC is the average weight of haemoglobin based on a certain volume of red cells.
Haemoglobin is a protein found in red blood cells and is responsible for carrying oxygen to the cells and tissues of the body. Measuring how much haemoglobin is present in red blood cells gives a good indication of how efficiently the cells are working.
A low haemoglobin level can indicate anaemia and MCH may help to determine the cause of the anaemia. High MCH levels can be caused by other forms of anaemia, particularly macrocytic anaemia or disease.
As part of a full blood count, mean cell haemoglobin levels are measured with mean cell volume, mean cell haemoglobin concentration and red cell distribution width. These measurements reflect the volume, size and haemoglobin content of red blood cells.
You can check your level of mean cell haemoglobin together with other red blood cells within Forth’s Vitality and Ultimate blood tests. For those who lead active lifestyles Forth also offers a home finger-prick blood test called Body Fit which includes mean cell haemoglobin blood tests as well as 16 other biomarkers.
Mean cell haemoglobin measures the amount of haemoglobin in each red blood cell. Haemoglobin is a vital protein in the human body and has an important function. The main role of haemoglobin is to transport oxygen from the lungs to all cells and tissues in the body. Approximately 96% of the dry weight of red blood cells is haemoglobin. The structure of haemoglobin consists of four heme molecules each of which contains an iron ion. Each of the iron ions can bind to one molecule of oxygen forming oxyhaemoglobin. When oxyhaemoglobin reaches a cell which requires oxygen, the oxygen dissociates from the haemoglobin and enters the cell.
Haemoglobin is also responsible for transporting carbon dioxide from the tissues to the lungs where it can be removed from the body. Carbon dioxide is a waste product of respiration, 80% of which is transported in the plasma. Unlike oxygen, carbon dioxide doesn’t bind to the oxygen binding site, instead, it attaches to the protein structure. The removal of carbon dioxide helps to keep the pH of the blood at a constant 7.4.
A low haemoglobin count can signify anaemia, particularly iron deficiency. Iron deficiency and other types of anaemia can cause some uncomfortable symptoms, but it can also negatively affect our physical and mental performance. Anaemia occurs when the body doesn’t have enough red blood cells to meet its needs and so can cause the symptoms which interrupt everyday life.
A high mean cell haemoglobin, on the other hand, can be a sign of macrocytic anaemia, a condition where red cells are larger than normal, usually larger than the nucleus of a small lymphocyte. A common cause of macrocytic anaemia is a nutrient deficiency.
If you are worried about your haemoglobin level or just want to check where you fall on the range, you can test your red blood cells with a simple at-home blood test.
Dehydration can cause abnormally high haemoglobin levels. Dehydration occurs when the body loses more water than it’s taking in, resulting in some unpleasant symptoms. For example, the condition can reduce your energy levels and make you feel fatigued which can affect your ability to carry out your daily activities.
Macrocytic anaemia is commonly caused by a vitamin B12 deficiency, usually caused by an insufficient dietary intake, particularly in individuals who follow a vegetarian or vegan diet.
Some of the causes of low haemoglobin levels include:
Anaemia may or may not cause symptoms. However, as the condition progresses you may notice symptoms, such as:
Vitamin B12 deficiency can cause many symptoms and the severity of the condition can worsen over time, especially if it is left untreated. The symptoms of vitamin B12 deficiency can include the normal symptoms of anaemia as well as:
A nutrient which is essential for red blood cell health is iron. Good sources of iron are red meat and liver. It is recommended that red meat is consumed once per week to help keep iron levels within normal parameters. Women who are of menstruating age need to keep their iron intake increased, particularly around the time of their periods. Individuals who follow a vegan or vegetarian diet will need to get their iron from plant-based sources.
Good food sources of iron are:
The absorption of iron from plant-based sources is better when vitamin C is present. For example, fortified breakfast cereals paired with a glass of orange juice. Tea can affect the absorption of iron, so you should refrain from drinking tea with your meals and switch to drinking it between meals. 
Iron levels can be influenced by too much or too little exercise. Not having enough iron can affect your muscles ability to recover following exercise.
Dehydration may result in an increased mean cell haemoglobin. This is because blood plasma volume is reduced, as water is distributed around the body to the cells and tissues which need it most. You should aim to drink little and often throughout the day. Thirst is an early sign of dehydration, so you should try to avoid getting thirsty. You may need to drink more if you are exposed to increased temperatures, are exercising or experiencing diarrhoea and vomiting.
A high mean cell haemoglobin level can be caused by macrocytic anaemia, a major cause of which is vitamin B12 deficiency. Therefore, it is important to ensure you are getting enough vitamin B12 in your diet. People who find it more difficult to get a good amount of B12 in their diet are those who follow a vegan diet. The reason for this is because much of the vitamin B12 comes from animal products. Vegans and possibly vegetarians may need to supplement their diet.
Good sources of vitamin B12 are:
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 Panawala, L. (2017). What is the Function of Hemoglobin in the Human Body? Pedia. Available at: https://www.researchgate.net/publication/313841668_What_is_the_Function_of_Hemoglobin_in_the_Human_Body
 Nagao, T and Hirokawa, M. (2017). Diagnosis and Treatment of Macrocytic Anaemia. J Gen Fam Med: 18(5), pp 200-204.
 Lane, D, J, R and Richardson, D, R. (2014). The Active Role of Vitamin C in Mammalian Iron Metabolism: Much More than Just Enhanced Iron Absorption. Free Radical Biology and Medicine: 75, pp 69-83.
 Zijp, I, M., Korver, O and Tijburg, L, B, M. (2000). Effect of Tea and Other Dietary Factors on Iron Absorption. Critical Reviews in Food Science and Nutrition: 40(5), pp 371-398.
 NHS. (2019). Treatment Vitamin B12 or Folate Deficiency Anaemia. Available at: https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/treatment/