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What Are MCH Levels?

Medically Reviewed by Sabrina Felson, MD on December 19, 2019

You might hear your doctor talk about MCH levels when they explain the results of certain blood tests. MCH is short for "mean corpuscular hemoglobin." It's the average amount in each of your red blood cells of a protein called hemoglobin, which carries oxygen around your body.

It's possible you'll learn about MCH when you get a blood test called a CBC (complete blood count). This test measures different parts of your blood, including red blood cells and white blood cells. Doctors use information from the CBC to calculate your MCH.

A similar measure to MCH is something doctors call "mean corpuscular hemoglobin concentration" (MCHC). MCHC checks the average amount of hemoglobin in a group of red blood cells.

Your doctor may use both measurements to help in a diagnosis of anemia. It's a condition caused by not having enough healthy red blood cells, or the red blood cells you do have don't work as well as they should. Anemia can make you feel extremely tired.

Getting a CBC

A CBC measures the different cells that make up your blood, including your:

  • Red blood cells
  • White blood cells, which fight infection
  • Hemoglobin
  • Platelets, which help your blood clot

You may have a CBC as part of your yearly physical exam or to check for a disease. Your doctor might give you this test if you have symptoms of a condition that affects your blood cell count.

To do a CBC, a nurse puts a needle into a vein in your arm. The needle attaches to a test tube, where the blood collects. A lab then analyzes the blood sample.

Symptoms and Causes of Anemia

Anemia can cause abnormal MCH readings on blood tests. Often a lack of iron causes anemia with a low MCH. ­Your body needs iron to make hemoglobin.

Pregnancy, blood loss, and weight loss surgery can all cause a drop in your iron levels and lead to iron-deficiency anemia or low hemoglobin and MCH levels.

When you have iron deficiency anemia, you may have symptoms like:

An anemia with a high MCH level could also be a sign that you don't have enough vitamin B12 or other nutrients. Your body needs vitamin B12 to make healthy blood cells, nerves, and DNA.

Signs of low vitamin B12 include:

  • Numbness or tingling in your hands and feet
  • Trouble walking or staying balanced
  • Trouble thinking
  • Tiredness
  • Weakness
  • Swollen tongue

An anemia with a high MCH is called macrocytic anemia. When you have this condition, your red blood cells are larger than normal.

Other causes of macrocytic anemia include:

Macrocytic anemia often doesn't cause symptoms. You may not know you have it until your doctor does a blood test for another reason.

If your body doesn't have enough vitamin B, you might have symptoms like:

Some conditions, including high cholesterol and high triglycerides, can make your MCH level seem high on a test when they're not really. Your doctor will help you interpret the test results.

Treatment of Anemia With a Low or High MCH

Which treatment you need depends on the condition that raised or lowered your MCH level.

If you have anemia, supplements can replace what your body lacks. You may also need treatment for the condition that caused your anemia. For example, if the cause is blood loss, birth control pills lessen heavy bleeding during periods. If you have a bleeding polyp or tumor, you may need surgery to remove it.

If your body doesn't have enough vitamin B12 or folate, your treatment will be to get more of these vitamins. They're in foods like fish, liver, green leafy vegetables, and fortified cereals. If you're a vegetarian or you don't eat enough foods that have vitamin B12, you can take supplements or get regular B12 shots from your doctor.

WebMD Medical Reference

Sources

SOURCES:

American Society of Hematology: "Anemia."

Case Reports in Neurological Medicine: "Reversible vitamin B12 deficiency presenting with acute dementia, paraparesis, and normal hemoglobin."

Harvard Medical School: "The A list of B12 foods," "Vitamin B12 deficiency can be sneaky, harmful."

Indian Journal of Hematology & Blood Transfusion: "Evaluation of macrocytosis in routine hemograms."

Mayo Clinic: "Anemia," "Complete Blood Count (CBC)," "Iron deficiency anemia," "Macrocytosis: What Causes It?"

Medscape: "Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC)."

National Heart, Lung, and Blood Institute: "Blood Tests."

NHS: "Symptoms: Vitamin B12 or folate deficiency anemia."

Sarma, P. Clinical Methods: The History, Physical, and Laboratory, Butterworths, 1990.

University of Rochester: "What Are Red Blood Cells?"

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