What Is MCH in a Blood Test?

A Measure of Hemoglobin in Blood Cells

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MCH (mean corpuscular hemoglobin) is a measurement of the amount of hemoglobin in a red blood cell. It is one of the standard measurements in a complete blood count (CBC) test. This is a common test that many adults have at some point in their life.

Low MCH levels often point to anemia. High MCH could indicate a condition like lung or kidney disease.

This article explains the role of hemoglobin and how the MCH is determined during a CBC test. It also explains what may cause levels that are higher or lower than normal.

A blood sample being held with a row of human samples

Andrew Brookes / Getty Images

Why Measure MCH?

Hemoglobin is a protein found in red blood cells. Oxygen and carbon dioxide attach to hemoglobin, which contains iron. When combined with oxygen, hemoglobin is what gives blood its red color.

MCH levels are measured as part of a CBC test. You may get a CBC test during an annual checkup or if your healthcare provider suspects a condition that affects the blood cell count, such as anemia.

A CBC details how many cells there are in the blood, as well as the physical characteristics of the cells, such as their size, shape, and content. Your MCH value typically parallels your mean corpuscular volume (MCV) level, which measures the actual size of your red blood cells.

Common Blood Tests

A CBC is a common blood test, but it's not the only one. Other blood tests include blood chemistry and blood enzyme tests and tests to assess for heart disease risk.

Understanding MCH in Test Results

The normal range of the MCH is between 27 and 31 picograms/cell.

There are specific symptoms and conditions associated with MCH levels that are both lower and higher than normal. Here is a general overview of what high and low MCH levels may mean for your health.

Low MCH Levels

Registering an MCH level below 27 picograms/cell is most commonly associated with anemia. It could also be a sign of:

  • An autoimmune disease
  • Cancer
  • Deficiency of certain nutrients, such as vitamin B12 or folic acid
  • Internal or external blood loss, often resulting from surgery, injury, or menstrual bleeding
  • Iron deficiency, almost always caused by blood loss
  • Kidney disease
  • Liver disease
  • Thalassemia, a common, inherited blood disorder caused by genetic mutations in the hemoglobin genes

People with low MCH levels may experience symptoms including:

  • Cold hands and feet
  • Dizziness
  • Fatigue
  • Pale skin (pallor)
  • Shortness of breath
  • Weakness

High MCH Levels

Having an MCH level above 31 picograms/cell is most commonly associated with the following conditions:

  • Certain types of kidney diseases, including kidney cancer
  • Congenital heart defect
  • Lung disease, including chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis
  • Polycythemia vera, a rare blood disease typically caused by a genetic mutation where the bone marrow produces too many red blood cells

People with high MCH levels may experience symptoms including:

  • Blood clots
  • Blurred or double vision
  • Dizziness
  • Headaches
  • Itching

Next Steps for Abnormal MCH Levels

If your MCH levels appear to be higher or lower than normal, your healthcare provider will do additional testing to determine the cause. The treatment options will depend on the cause.

Keep in mind that there are many reasons why MCH levels fall outside the normal range, and it may not indicate a health condition. It could be a side effect from a medication. It could even be because you live in a high-altitude region. Follow-up tests can help rule out any health conditions and provide reassurance.

Summary

The mean corpuscular hemoglobin (MCH) measurement is part of a complete blood count (CBC) test. The MCH represents the average amount of hemoglobin in a cell. Hemoglobin is a protein in red blood cells that carries oxygen and carbon dioxide.

A low MCH can indicate conditions like anemia and thalassemia. High levels might be due to lung or kidney disease. If your levels are abnormal, your healthcare provider will determine the cause and appropriate treatment.

A Word From Verywell

MCH levels represent only one piece of what you might call the "healthcare puzzle." Other factors, including family history and lifestyle, also provide crucial information about your overall health and the likelihood of having a particular condition. Uncovering this information requires that you be honest and open with your healthcare provider. Doing so can put your MCH levels into clearer focus.

Frequently Asked Questions

  • What causes low MCH in a blood test?

    Low levels of mean corpuscular hemoglobin (MCH) can be caused by anemia, iron deficiency, vitamin B12 or folic acid deficiency, cancer, kidney disease, autoimmune diseases, liver disease, or thalassemia (a hemoglobin disorder). Low MCH can also be caused by blood loss due to surgery, an injury, menstrual bleeding, or bleeding in the gastrointestinal tract.

  • What is in blood?

    Human blood consists of plasma, red blood cells, white blood cells (leukocytes), and platelets (thrombocytes). Hemoglobin is found in red blood cells.

  • What is MCV?

    Mean corpuscular volume (MCV) measures the average size of red blood cells in a blood sample.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. National Heart Lung and Blood Institute. Blood tests.

  3. Huang P, Liu C, Li B, et al. Preoperative mean corpuscular hemoglobin affecting long-term outcomes of hepatectomized patients with hepatocellular carcinomaMol Clin Oncol. 2016;4(2):229-236. doi:10.3892/mco.2015.705

  4. Cleveland Clinic. Hemoglobin test.

  5. MedlinePlus. Hemoglobin test.

  6. Cleveland Clinic. High hemoglobin count.

  7. University of Rochester Medical Center. Overview of blood and blood components.

By Elizabeth Yuko, PhD
Elizabeth Yuko, PhD, is a bioethicist and journalist, as well as an adjunct professor of ethics at Dublin City University. She has written for publications including The New York Times, The Washington Post, The Atlantic, Rolling Stone, and more.