What Does It Mean if Your MCV Is High?

Medically Reviewed on 3/4/2022

What are the symptoms of high MCV?

Mean corpuscular volume (MCV) is a value related to your red blood cells.
A higher MCV value indicates that the red blood cells are larger than the average size.

Mean corpuscular volume (MCV) is a value related to your red blood cells

  • An average MCV score is between 80 and 95.
  • If the MCV goes up to an extreme of 125, it may indicate vitamin B12, folate deficiencies, or cold agglutinin disease.

A higher MCV value indicates that the red blood cells are larger than the average size.

What are the symptoms of high MCV?

If your MCV goes up, it could indicate:

  • Low vitamin B12 level
  • Folate deficiency (folic acid is a nutrient)
  • Liver disease
  • Alcoholism
  • Hypothyroidism
  • Carbon monoxide poisoning
  • Aplastic anemia (a condition where the body stops producing sufficient red blood cells)
  • Cold agglutinin disease (a condition where the body’s immune system attacks your red blood cells and destroys them)
  • Chronic hypoxia (low oxygen levels in the blood)
  • Benign familial macrocytosis (high MCV level due to a genetic defect)
  • Myelodysplastic syndrome (a group of disorders caused when something disrupts the production of blood cells)

What is MCV? Normal, high, and low

The mean corpuscular volume (MCV) measures the average size of the red blood cells. The average MCV ranges from 80 to 100 femtoliters (fL). There are three conditions associated with MCV, which include:

  • Microcytic: MCV level below 80 fL
  • Normocytic: MCV level between 80 and 100 fL
  • Macrocytic: MCV level above 100 fL

A low or high MCV level may indicate health issues. MCV is calculated according to the following formula:

  • MCV (fL) = [Hematocrit (%)*10]/[RBC count (106/µL)]

MCV is the most useful indicator to diagnose anemia. MCV values seem to be higher than average in people taking zidovudine or in people with vitamin B12 and folic acid deficiencies.

MCV can help narrow down possible diagnoses.

What does an MCV test tell you?

The physician may order a mean corpuscular volume (MCV) test if you exhibit these symptoms of a blood disorder:

The physician may also order an MCV test to differentiate several types of anemia. MCV also helps detect abnormalities with white blood cells or platelet.

What else does MCV diagnose?

Apart from anemia, the mean corpuscular volume (MCV) test also helps:

  • Forecast mortality in esophageal cancer.
  • Estimate prognosis with chronic kidney disease.
  • Predict the efficiency of chemotherapy and radiation with rectal cancer.
  • Evaluate cognitive function (a higher MCV in older adults is associated with inferior cognitive function).

Researchers have found that patients with kidney disease and high MCV levels were at greater risk of death. They are over 3.5 times more likely to suffer from heart disease than those who had a normal MCV.


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What is a normal MCV in children?

What Is a Normal MCV in Children
Mean corpuscular volume (MCV) is an indicator of anemia and other blood disorders. Learn about normal ranges for children according to age group

Mean corpuscular volume (MCV) is a measurement of the average size of red blood cells (RBCs). MCV is part of complete blood count—a routine screening test that analyzes the other two blood components, white blood cells, and platelets.

MCV is an indicator of reduced red blood cell circulation in the body, as seen in anemia and vitamin B12, and folic acid deficiencies.

Normal MCV in adults ranges from 80-100 fL.

Normal pediatric ranges are shown in the table below.

Table: Normal MCV ranges for children by age group
Age MCV range (in fL)
0 to 1 month 88 to 123
1 to 3 months 91 to 112
3 to 6 months 74 to 108
6 months to 1 year 70 to 85
2 to 3 years 74 to 89
4 to 6 years 77 to 91
7 to 10 years 78 to 92
11 to 14 years 80 to 95
15 to 18 years 81 to 96

What causes high MCV in children?

High MCV is indicative of a larger-than-average size of red blood cells (RBCs), which could be due to:

  • Folate deficiency is the most common cause of high MCV.
  • Vitamin B12 deficiency
  • Liver disease
  • Hypothyroidism
  • Aplastic anemia (anemia due to bone marrow development failure)
  • Myelodysplastic syndrome (a group of disorders in which RBCs do not mature)
  • Chronic hypoxia (reduced amount of oxygen in the tissues)
  • Benign familial macrocytosis (an inherited syndrome that leads to RBCs that are larger than normal)
  • Leukemia

What causes low MCV in children?

Low MCV is indicative of a smaller-than-average size of red blood cells (RBCs), which could be due to:

What causes anemia in children?

Causes of anemia in children vary depending on their age, gender, and ethnicity:

  • Birth to 3 months:
    • Physiological anemia, which is a normal developmental response to increased tissue oxygenation
    • Pathologic anemia, which may be due to other causes such as:
      • Blood loss
      • Hemolytic disease (Rh or ABO incompatibility)
      • Glucose-6-phosphate dehydrogenase deficiency
    • Congenital infections
    • Twin-twin transfusion
  • 3-6 months:
    • Hemoglobinopathy
  • Children and adolescents:
    • Cow milk intake
    • Menarche in female children
Medically Reviewed on 3/4/2022
Image Source: iStock Images


Henry’s Clinical Diagnosis and Management by Laboratory Methods E-Book, 23rd Edition


Pediatric Reference Ranges: https://www.healthcare.uiowa.edu/path_handbook/appendix/heme/pediatric_normals.html

Brittany Maner. Mean Corpuscular Volume. NIH: https://www.ncbi.nlm.nih.gov/books/NBK545275/

Choladda Curry. Mean Corpuscular Volume (MCV). Medscape: https://emedicine.medscape.com/article/2085770-overview#a1