MCH Blood Test: Normal Range, Low & High Results Explained

Marcela Lemos
Clinical review: Marcela Lemos Biomedical Scientist CRBM/PE #08598
Created by: Tua Saude editing team

An MCH blood test is a measurement included in a complete blood count (CBC). It measures the average amount of hemoglobin inside each red blood cell and can help evaluate different types of anemia.

An MCH blood test is interpreted along with other blood test results, such as MCV, to help identify conditions like hyperchromic, normochromic, and hypochromic anemia. High or low MCH levels may be linked to iron deficiency, vitamin B12 or folate deficiency, thyroid disorders, alcohol use, or inherited blood disorders such as thalassemia.

Normal MCH values vary by age, with typical adult values ranging from 27 to 32 pg per red blood cell. MCH results should be interpreted by a healthcare provider, who can determine the underlying cause of abnormal levels and recommend the most appropriate treatment when needed.

gloved hands using a dropper to put a blood sample on a slide

Reference values

Normal mean corpuscular hemoglobin (MCH) values are:

  • Newborn: 31 - 37 pg

  • 1 month: 30 - 36 pg

  • 2 months: 27 - 33 pg

  • 3 to 6 months: 24 - 30 pg

  • 1 year: 25 - 29 pg

  • 2 to 6 years: 24 - 30 pg

  • 6 to 12 years: 25 - 33 pg

  • Adults: 27 - 32 pg

These values help show how much hemoglobin is present in each red blood cell. Low values can make red blood cells look paler than normal, while high values can make them look darker than normal.

What results mean

The main types of MCH changes are:

1. High MCH

In adults, high MCH values (above 32 pg) may occur due to heavy alcohol use, certain medications, or thyroid disorders.

It is also common to see red blood cells that are larger than normal. This may be a sign of megaloblastic anemia, which can happen due to vitamin B12 or folic acid deficiency.

2. Low MCH

In adults, MCH values below 27 pg indicate hypochromia. This means the red blood cell is lighter in color than normal due to a lower concentration of hemoglobin in each red blood cell.

Low MCH may be caused by iron-deficiency anemia due to low iron levels. According to the CDC, it may also be linked to thalassemia, an inherited blood disorder that affects hemoglobin, an important protein in red blood cells.

It is also common to see red blood cells that are smaller than normal, known as microcytic red blood cells. Other CBC parameters and any additional test results ordered by a healthcare provider should be evaluated to identify the cause of hypochromia and microcytosis.

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References
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