What is MCH?

MCH stands for “mean corpuscular hemoglobin.” An MCH value refers to the average quantity of hemoglobin present in a single red blood cell. Hemoglobin is the protein in your red blood cells that transports oxygen to the tissues of your body.

Your MCH value is related to two other values, mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC). Together, MCH, MCV, and MCHC are sometimes referred to as red blood cell indices.

MCV is a measurement of the average size of your red blood cells. MCH results tend to mirror MCV results. This is because bigger red blood cells generally contain more hemoglobin while smaller red blood cells tend to have less.

MCHC is a calculation of the amount of hemoglobin per unit volume in a single red blood cell. The difference between MCH and MCHC is that the MCHC measurement takes the volume or size of the red blood cell into account while MCH does not.

How is MCH level determined?

Your MCH level is determined with a complete blood count (CBC) panel. Your doctor will order a CBC panel to screen for a large range of conditions, including anemia and infection. The CBC tests red and white blood cells, as well as platelets. MCH is calculated using the red blood cell analysis.

MCH is calculated by dividing the amount of hemoglobin in a given volume of blood by the number of red blood cells present.

Normal range

The normal range for MCH is between 27.5 and 33.2 picograms (pg).

Low MCH causes and symptoms

An MCH value calculated below 27.5 pg is considered low MCH. This means that there’s a low amount of hemoglobin present per red blood cell.

Causes

A low MCH value typically indicates the presence of iron deficiency anemia. Iron is important for the production of hemoglobin. Your body absorbs a small amount of iron that you eat in order to produce hemoglobin. Some of the general causes of iron deficiency include eating a diet that is low in iron, major surgery or trauma, or blood loss.

In more rare cases, low MCH can be caused by a genetic condition called thalassemia. In this condition, production of hemoglobin is limited. This means there aren’t as many red blood cells circulating in your bloodstream.

Symptoms

If you have a low MCH value, you may experience the following symptoms:

High MCH causes and symptoms

An MCH value calculated above 33.2 pg is considered high MCH. This means that there is a larger amount of hemoglobin present per red blood cell.

Causes

High MCH value can often be caused by anemia due to a deficiency of B vitamins, particularly B-12 and folate. Both of these vitamins are required by your body in order to make red blood cells. These types of anemia can develop if your diet is low in B vitamins or if your body does not absorb B-12 or folate properly. It’s important to be aware of the symptoms of a B-12 deficiency.

Symptoms

If you have a high MCH value, you may experience the following symptoms:

  • shortness of breath
  • chest pain
  • fast heartbeat
  • fatigue or weakness
  • very pale or yellowish skin
  • headache

If you have anemia that’s due to B-12 deficiency, you may also experience:

  • tingling or “pins and needles” in your hands or feet
  • nausea or vomiting
  • bloating and gas
  • mental symptoms, such as depression or confusion

If you have anemia due to folate deficiency, you could experience the following additional symptoms:

Treatment for low or high MCH

Low MCH

Treatment for low MCH caused by iron deficiency can include adding iron-rich foods to your diet (there are even vegetarian options) and taking iron supplements. In rare cases, such as when symptoms are severe or blood loss has occurred, you may need a blood transfusion.

People with mild thalassemia may not require treatment. However, blood transfusions may be required if your symptoms are severe.

High MCH

Treatment for anemias caused by B-12 or folate deficiencies are commonly treated by lifestyle changes, such as adding foods rich in vitamin B-12 and folate to your diet. Your doctor may also recommend taking supplements of these vitamins to further boost your B-12 and folate levels or, if absorption is a problem, prescribe B-12 injections.

What’s the outlook?

The outlook for people with abnormal MCH values depends on the condition that’s causing it.

Low MCH values are often caused by iron deficiency anemia. Typically, this condition can be treated with lifestyle changes including consuming foods rich in iron as well as taking iron supplements. In the rare case that your low MCH value is caused by thalassemia, you may require blood transfusions if your symptoms are severe.

High MCH values caused by a deficiency of the vitamins B-12 or folate can also often be treated with changes to your lifestyle that include dietary modifications and supplements, or injectable B-12.

If you’re concerned about your MCH results, be sure to talk to your doctor about them. Together, you can decide on the best way to move forward.