MCH Blood Test: High, Low, Normal (Evidence Based)

MCH Blood Test: What Do MCH Levels in Blood Mean?

MCH blood test is usually done as part of a complete blood count (CBC) test that doctors use to check your general health. MCH stands for mean corpuscular hemoglobin and is the amount of hemoglobin in your red blood cells. Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body’s tissues and returns carbon dioxide from the tissues back to the lungs. Some of the causes of high or low MCH levels are iron deficiency, lack of vitamin B12, thyroid issues, or problems with your liver function.

Normal MCH levels mean that your body is producing enough hemoglobin. This also means that there are no underlying medical conditions that are causing hemoglobin to get destroyed too quickly.

Having low or high levels of hemoglobin can tell if you have different types of anemia. If your complete blood count test shows that you have anemia and abnormal MCH levels, you might also feel fatigued, have a rapid heartbeat, palpitations, and difficulty concentrating.

This article looks at what your MCH blood test means and what it tells about your health. You will also find out what to do if you have low mean corpuscular hemoglobin levels (low MCH).

What is MCH Blood Test?

Hemoglobin is an important molecule in your red blood cells that helps to carry oxygen to body tissues. The MCH is a calculation of the average amount of hemoglobin inside a single red blood cell.

The only way that doctors can test MCH levels in a lab test is to use it as part of a complete blood count (CBC). Dr. Brian Yang Merritt on Medscape says that MCH results are derived from measuring the concentration of hemoglobin in your red blood cell count (RBC).1

The MCH blood test is also related to the MCHC blood test which measures the concentration of hemoglobin in a given volume of red blood cells. Together, the MCH and MCHC indices are used to help doctors determine the cause of certain medical conditions.

What is CBC Blood Test?

A CBC (complete blood count) is a panel of tests that evaluates the three types of cells that circulate in the blood:

According to doctors from the Mayo Clinic, the CBC blood test is used to assess your general health. The CBC can then be used by doctors to diagnose a variety of disorders including infections, anemia, and leukemia. The CBC tests for abnormalities in red blood cells, white blood cells, hemoglobin, plasma, and platelets.2

What Are Normal MCH Levels?

According to the book Clinical Methods in the chapter “Red Cell Indices,” normal MCH levels are 29 ± 2 picograms (pg) per red blood cell in adults. This figure along with calculating the size of red blood cells (MCV) and the concentration of hemoglobin (MCHC) give doctors an idea of your general health.3

What Are the Symptoms of Low MCH Levels?

A low MCH is medically called hypochromic, because there is less haemoglobin in the red blood cells. If your MCH levels drop temporarily, you may not have any symptoms. However if low MCH levels persist, you may have these symptoms of low MCH:

  • Weakness
  • Constant fatigue
  • Dizziness
  • Pale skin

These low MCH symptoms are similar to the symptoms of anemia. Checking for normal MCH levels is an important step in looking for signs of anemia. Even if you have enough red blood cells, you could still be anemic if you don’t have enough hemoglobin in each cell. Anemia can cause extreme fatigue, pale skin with no color, shortness of breath, chest pain, and cold hands and feet.

What Causes Low MCH Levels?

Some of the conditions that can cause low MCH levels are iron deficiency anemia, microcytic anemia, vitamin deficiencies, celiac disease, and gastric surgery.

Doctors from the Mayo Clinic say that to produce enough red blood cells with enough hemoglobin, your body needs iron, vitamin B-12, folate, and other nutrients. If your body is lacking these nutrients or red blood cells are getting destroyed too quickly, the result will be low MCH levels.5

Iron deficiency anemia and low MCH levels

Your lab test results could show lower than normal MCH if you don’t get enough iron in your diet which results in iron deficiency anemia.

Iron deficiency anemia is a condition in which blood lacks adequate healthy red blood cells. Without enough iron, your body can’t produce enough hemoglobin that enables the red blood cells to carry oxygen. As a result, iron deficiency anemia can leave you tired and short of breath.

Dr. Stanley Schrier says that having an iron deficiency will cause low MCH, MCHC and Hematocrit (Hct) levels. This can result in fewer red blood cells in your body and cause you to suffer from the symptoms of anemia.6

Celiac disease causes low MCH levels

Celiac disease can cause low MCH levels in a blood test result because the condition prevents iron being absorbed into the body.

According to the Indian Journal of Pediatrics, iron deficiencies are commonly found in people with celiac disease. To address the iron deficiency in celiac patients, doctors put patients on a strict gluten-free diet and provide them with iron supplements. This helped to reduce the symptoms of celiac disease and boost hemoglobin levels in the blood.7

There are other symptoms of being sensitive to gluten in products. Some of these are joint pain, digestive issues like greasy stool, tingling sensations in your body, and inflammatory skin disorders.

Gastric surgery

If you have had gastric surgery, you might find that your blood test results show low MCH levels.

Like with celiac disease, gastric surgery can hinder how much iron the body can absorb. The journal BioMed Research International reported on the connection between anemia and gastric bypass surgery. It was found that infections, chronic diseases, and aging can cause inflammation and promote anemia in people who’ve had gastric surgery.8

Thyroid dysfunction and MCH levels

Thyroid dysfunction can cause low or high MCH levels.

According to the journal Polish Archives of International Medicine, different forms of anemia can develop from thyroid dysfunction. Both hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid) can cause abnormalities in MCH levels.9

However, it is unclear if thyroid dysfunction always causes low MCH or high MCH levels. For example, the Iranian Journal of Pediatric Hematology Oncology reported that both MCH and MCHC levels were lower in people with overactive and underactive thyroids.10

On the other hand, studies published by the European Journal of Endocrinology found that MCH levels were increased with both types of thyroid disorder.11

When doctors suspect a thyroid issue, they will test your blood specifically for thyroid hormone to test if you have a thyroid disorder.

Treatment for Low MCH Levels and How to Increase MCH

If your low MCH level is caused by anemia, it’s important to increase your iron intake to improve your blood work.

Eat more iron-rich foods to increase MCH

The best way to increase iron levels in your blood and bring your MCH readings up to normal levels is to consume more iron-rich foods.

According to Dr. Christine Mikstas on WebMD, some of the best dietary sources of iron that are easily absorbed by the body are beef or chicken liver, oysters, cooked beef, and canned sardines in oil.

There are also plenty of vegetable and plant-based sources of iron. Some of the best sources include cooked beans, tofu, pumpkin seeds or sesame seeds. Also, kidney beans, dried apricots, and iron-enriched foods can help to increase your iron intake and prevent anemia.

For more information on the best kinds of foods to eat to prevent anemia, please read my article on how to increase iron levels in your blood.

Take iron supplements to treat anemia

Another way to increase MCH and MCHC levels in your blood is to take iron supplements to treat anemia.

Although it is always best to get your vitamins and minerals from dietary sources, sometimes iron supplements are needed to treat anemia.

The American Journal of Medicine reports that adults need around 20mg of iron daily. If a person has had gastric surgery or suffers from celiac disease, doctors may recommend taking more iron. The report also noted that a person should take vitamin C as this helps to increase iron absorption. If you have anemia, you should avoid drinking tea for at least an hour after eating as tea hinders iron absorption.14

Cook with iron cookware

If you need to increase iron levels in your blood, you should switch to cooking with iron cookware. Doctors from the Mayo Clinic recommend cooking with iron pots and pans to get more iron into your diet.15

Cooking with iron cookware will help to avoid the dangers associated with cooking with aluminum.

What are the Symptoms of High MCH Levels?

Because high MCH levels can also cause symptoms of anemia, they are usually similar to having low MCH levels. A high MCH with anemia is known as hyperchromic anemia.

Some of the symptoms of high MCH include extreme fatigue, pale skin with no color, shortness of breath, chest pain, and cold hands and feet.

What Causes High MCH Levels?

Here are some of the main causes of elevated MCH (hyperchromic):

Liver disease and high MCH Levels

High MCH levels many make doctors examine your liver function to check that there is no liver disease.

High MCH levels can cause macrocytic anemia and this is associated with liver dysfunction. According to the journal Management of Anemia, different types of anemia are associated with liver disease. Gastrointestinal problems associated with liver disease can also result in poor iron absorption from your diet.12

Vitamin B12 deficiency causes higher than normal MCH

A vitamin B12 deficiency can be a reason for blood test results to show higher than normal MCH levels.

The book Clinical Methods says that megaloblastic anemias are often caused by low levels of folate or vitamin B12.3

Vitamin B12 deficiencies are more common than most people realize. Therefore, it’s important to know the symptoms of low levels of vitamin B12. These can lead to depression, extreme fatigue, memory loss, difficulty sleeping, and mood swings.

Drinking too much alcohol and high MCH

Overindulgence in alcohol over many years can cause anemia and higher than normal levels of mean corpuscular hemoglobin in your red blood cells.

For example, Dr. Vincent Herrin on Medscape says that megaloblastic anemia is often associated with alcoholism, vitamin B12, and folate deficiencies. Chronic alcohol use affects bone marrow production of red blood cells and causes symptoms associated with anemia. Usually, abstaining from alcohol for a few months will help MCH levels to normalize.13

Certain medications

According to the Journal of General Family Medical Practice, certain medications can cause folate and vitamin B12 deficiencies. In fact, some reports indicate that nearly 40% of patients with macrocytosis anemia have been taking medications that interfere with their hemoglobin levels.14 A macrocytosis anemia is an anemia in which the red blood cells (erythrocytes) are larger than their normal volume.

Treatment for High MCH Levels and How to Decrease MCH

If the lab test results for MCH show high levels, your doctor will carry out further tests to find the underlying cause.

If the elevated MCH levels are due to a liver dysfunction, it is important to avoid habits that can damage your liver. These include limiting alcohol consumption to safe levels, getting enough sleep, stopping smoking, and enjoying a balanced, nutritious diet. This will also help to prevent fatty liver disease.

Other Related Blood Tests

MCHC blood test

The MCHC blood test is related to the mean corpuscular hemoglobin test (MCH), however, this checks for the concentration of hemoglobin in your red blood cells.

MPV blood test

MPV stands for mean platelet volume and measures the average size of your platelets. This can help doctors diagnose certain anemia conditions, inflammatory diseases, and check for a vitamin D deficiency.

For more information on MPV blood tests, please read my article on what MPV can tell about your health.

RDW blood test

Measuring the difference in size and volume of your red blood cells is called the RDW blood test, or red cell distribution width. Abnormal RDW readings could be a sign of cardiovascular problems, kidney or liver dysfunction, or autoimmune conditions.

MCV blood test

The MCV blood test checks the mean corpuscular volume of your red blood cells and can help doctors diagnose certain health conditions. The MCV test can help look for certain vitamin deficiencies like iron, folate, and vitamin B12. It will also show if your liver and internal organs are functioning properly.

Read my other related articles:

Article Sources

  1. Medscape. Mean corpuscular hemoglobin.
  2. MayoClinic. Complete blood count (CBC).
  3. NCBI. Red cell indices.
  4. MedicineNet. Hemoglobin.
  5. MayoClinic. Anemia.
  6. UpToDate. Anemia caused by low iron in adults.
  7. Indian J Pediatr.2003 Dec;70(12):955-8.
  8. BioMed Res Int. 2013 (2013), Article ID 205467, 8 pages.
  9. Pol Arch Intern Med.2017 May 31;127(5):352-360.
  10. Iran J Ped Hematol Oncol. 2013; 3(2): 73–77.
  11. Eur J Endocrinol. February 1, 2010 162 295-305.
  12. Management of Anemiapp 129-142.
  13. Medscape. Macrocytosis.
  14. Am J Med. 2008 Nov; 121(11): 943–948.
  15. MayoClinic. Iron supplement.

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