A high MCH means red blood cells carry more hemoglobin than usual, often linked to vitamin B12 or folate deficiency. See a doctor for testing.
Meaning
MCH (mean corpuscular hemoglobin) is the average hemoglobin in a red blood cell. Normal is about 27 to 33 picograms.
Causes of high MCH
- Vitamin B12 deficiency.
- Folate deficiency.
- Liver disease.
- Alcohol use.
- Hypothyroidism.
- Some medicines.
Linked
Macrocytic anemia, with large red cells (high MCV).
See a doctor
Further tests (B12, folate).
What MCH measures
Mean corpuscular hemoglobin (MCH) is the average amount of hemoglobin in a single red blood cell, reported in picograms (pg). The usual adult reference range is about 27 to 33 pg, depending on the lab. A value above 33 pg is called high.
- High MCH usually occurs with macrocytic anemia, where red cells are large. Common causes are vitamin B12 deficiency, folate deficiency, alcohol use, liver disease, hypothyroidism and some medicines such as methotrexate and hydroxyurea.
- Myelodysplastic syndromes are a less common cause in older adults.
- MCH is read alongside MCV (mean cell volume) and MCHC.
Next steps
A doctor reviews the full blood count, hemoglobin and symptoms such as fatigue, numbness or pale skin. Tests may include B12, folate, thyroid and liver tests. Treatment depends on the cause, such as B12 injections or supplements. Do not self-treat with high-dose vitamins without testing, as folate can mask B12 deficiency.
What MCH measures
Mean corpuscular hemoglobin (MCH) is the average amount of hemoglobin in each red blood cell, normally about 27 to 33 picograms. A high MCH is usually seen with macrocytic anemia, when red cells are larger than normal. Common causes are vitamin B12 or folate deficiency, alcohol use, liver disease, hypothyroidism and certain medications such as methotrexate.
Next steps
Doctors interpret MCH with MCV, MCHC and hemoglobin. Follow up tests include B12, folate, thyroid and liver tests. Treatment depends on the cause, such as B12 injections or supplements. A mildly high value with normal hemoglobin may need only monitoring. Lab ranges differ.
Reference range and what MCH measures
Mean corpuscular hemoglobin (MCH) is the average amount of hemoglobin in one red blood cell, reported in picograms (pg). Most laboratories use a reference range of about 27 to 33 pg, though ranges differ slightly by lab and age. It is calculated as hemoglobin divided by red blood cell count. MCH is reported together with MCV (cell size) and MCHC (hemoglobin concentration), and the three usually move in the same direction.
Common reasons for a high value
A high MCH usually accompanies large red cells (macrocytosis). The most common causes are vitamin B12 deficiency, folate deficiency, alcohol use, hypothyroidism, liver disease, myelodysplastic syndromes and certain drugs such as methotrexate, hydroxyurea and some antiretrovirals. Newborns normally have higher values. A high reading alone is not a diagnosis. Doctors compare it with MCV, a blood smear, B12, folate, thyroid tests and liver tests, and treatment targets the cause, for example B12 injections or tablets for deficiency.
Based on data from the Mayo Clinic and MedlinePlus
