What Is MCH?
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 of a protein called hemoglobin in each of your red blood cells. Hemoglobin 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.
Your doctor may use this measurement to help in a diagnosis of some nutrient deficiencies or problems with your liver.
CBC Test
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.
Normal MCH Levels
MCH levels vary, so there is a range that doctors consider normal. MCH is measured in picograms per cell, or (pg/cell). For adults of all ages and children, normal MCH levels are 27 to 31 pg/cell. For newborns, they are 32 to 34 pg/cell.
Low MCH Level
The most common reasons for low MCH levels are:
Anemia. This happens when your body doesn't have enough healthy red blood cells to carry oxygen around your body. The most common cause is low levels of the mineral iron. It's also caused by low levels of vitamin B12 and folate.
Hemoglobinopathies. These are inherited (passed down through family) blood disorders where there's a problem with the shape of hemoglobin or with how your body makes it. Thalassemia and sickle cell disease are two examples.
Low MCH level symptoms
Your symptoms will be related to what is causing your low MCH levels.
Symptoms of anemia:
- Fatigue
- Weakness
- Shortness of breath
- Pale skin
- Feeling dizzy or lightheaded
Symptoms of thalassemia:
- Anemia symptoms
- Abdominal swelling
- Dark-colored pee
Symptoms of sickle cell disease:
- Anemia symptoms
- Dark-colored pee
- Yellowish eyes
- Pain and swelling in hands and feet
- Episodes of body pain
High MCH Level
A high MCH level means your red blood cells are larger than normal. This is called macrocytosis. Usually, there is nothing to be worried about if you have macrocytosis. But it can be caused by macrocytic anemia. If you have macrocytic anemia, your bone marrow makes red blood cells that are too large.
High MCH levels could also be caused by:
Some forms of liver disease
Drinking too much alcohol
Some blood cancers
Too little vitamin B12 or folate
Hypothyroidism, when your body makes too little thyroid hormone
Medicines, including chemotherapy medications, antibiotics, and antivirals
High MCH level symptoms
A high level of MCH itself doesn't cause symptoms and might only be found with a blood test. If you do have symptoms, they would be related to the condition that caused the high MCH levels.
For example, if you have liver disease, you might have pain in the upper part of your abdomen, loss of appetite, fatigue, or yellowing of your skin. If you have hypothyroidism, you might be tired, gain weight, have numbness and tingling in your hands and fingers, and have sore muscles. Low levels of vitamin B12 and folate can cause symptoms of anemia, like fatigue, dizziness, and shortness of breath.
Takeaways
Your doctor can find out if your MCH levels are too high or low through a blood test. There are several causes for abnormal MCH levels. Some are common, such as anemia and medication side effects. But they can also be caused by illnesses such as blood cancers or inherited blood disorders. Your treatment plan will depend on the cause.