What Does a High or Low Mean Corpuscular Volume (MCV) Mean?

A mean corpuscular volume (MCV) is a type of blood test that measures the size of your red blood cells. It is included in a routine panel of tests called a complete blood count (CBC). For adults, MCV levels normally fall between 80 and 100 femtoliters (fl).

Red blood cells carry oxygen through your body. A low MCV means that your red blood cells are smaller than average, possibly indicating iron deficiency anemia. A high MCV means your red blood cells are larger than average, which could indicate liver disease or a vitamin deficiency.

The interpretation relies heavily on other blood test results in the CBC. An abnormal MCV may suggest a health issue but cannot diagnose any condition on its own.

Purpose of an MCV Blood Test

Mean corpuscular volume (MCV) is used to measure the average size of red blood cells (also known as erythrocytes ). The term corpuscle describes a living cell, such as a red blood cell.

MCV is measured by multiplying the total volume of blood (both blood cells and plasma) by the proportion of blood that is purely cellular (referred to as hematocrit or HCT). That value is then multiplied by 10 and divided by the total number of erythrocytes (called the red blood bell count, or RBC).

The calculation can be mathematically described as follows:

MCV = (HCT % x 10) ÷ RBC

The MCV test is not used alone but interpreted along with other tests in the CBC. When interpreted as such, the MCV test can be useful for:

• Diagnosing anemia (a disorder that reduces the ability of red blood cells to carry oxygen to tissues)
• Determining the causes of anemia based on whether your red blood cells are small (microcytic), large (macrocytic), or normal (normocytic anemia).

The MCV can also change with certain diseases and may be useful for diagnosing or monitoring conditions that cause a change in red blood cell volume. This includes liver disease, chronic kidney disease, and certain vitamin deficiencies.

Who Needs an MCV Test?

The CBC is a routine blood test performed during a medical check-up to see if there are any problems with the composition or concentration of your blood cells. The MCV is one of many tests used to assess your general health.

However, the MCV can also be used if you have signs and symptoms of anemia, such as:

• Fatigue
• Lethargy
• Pale skin
• Dizziness
• Headaches
• Shortness of breath
• Sore tongue
• Brittle nails
• Hair loss
• Rapid heartbeats
• Chest pains
• Pounding or whooshing sounds in your ears ( pulsatile tinnitus )
• A craving for ice ( pagophagia )

What Is a Normal MCV?

A normal MCV in adults ranges from 80 to 100 fl. Even so, levels can vary based on sex and age and tend to rise as people get older.

This is evidenced by a 2022 study published in the Journal of Cellular Molecular Medicine which showed how MCV levels can change in otherwise healthy males and females as they age.

Age	Female	Male
Under 10	82.4 fl	81.9 fl
10 to 19	87.6 fl	87.3 fl
20 to 29	90.0 fl	89.8 fl
30 to 39	90.4 fl	90.4 fl
40 to 49	91.0 fl	91.3 fl
50 to 59	91.1 fl	92.0 fl
60 to 69	91.6 fl	92.5 fl
70 to 79	92.1 fl	93.0 fl
80 to 88	92.5 fl	93.6 fl

What a Low MCV Means

A low MCV means that your red blood cell volume is under 80 fl. Also referred to as microcytosis , this is characteristic of certain medical conditions, such as:

• Iron-deficiency anemia: This is a type of microcytic anemia in which you lack sufficient iron in your blood. Iron is essential for the formation of red blood cells (called erythropoiesis ), and the lack of iron not only reduces their numbers but their size as well.
• Thalassemia: This group of inherited blood disorders causes a lack of hemoglobin (Hb), the protein that carries oxygen in red blood cells. Microcytic anemia can develop as excessive amounts of red blood cells are destroyed due to low Hb levels.
• Sideroblastic anemia: This is an inherited form of microcytic anemia caused by the abnormal utilization of iron during erythropoiesis.
• Anemia of chronic disease: Chronic diseases ranging from HIV and hepatitis B to lupus and ulcerative colitis can interfere with how the body uses iron while reducing the production of hormones essential to red blood cell production.
• Lead poisoning: Chronic lead exposure interferes with heme, the iron-containing compound that makes up part of hemoglobin. This can not only lead to a reduction in red blood cell numbers but also their size.
• Spherocytosis: This is an inherited blood disorder that causes a rapid breakdown of red blood cells due to a defect in their membranes. Spherocytosis also interferes with the formation of cells, leading to microcytosis.

What a High MCV Means

A high MCV means your red blood cells have a volume greater than 100 fl. The increased cellular volume may be due to conditions that cause the increased destruction of red blood cells, known as hemolysis .

To compensate for the loss, the bone marrow will start to churn out larger red blood cells, which have decreased function. This is known as macrocytosis .

Macrocytosis may also be caused by vitamin deficiencies that prevent immature red blood cells (called reticulocytes ) from maturing. Instead, they become abnormally large and start to crowd out normal red blood cells, leading to macrocytic anemia.

Conditions associated with macrocytosis include:

• Vitamin B12 deficiency
• Folate deficiency
• Liver disease
• Uncontrolled diabetes
• Alcohol use disorder
• Hypothyroidism
• Smoking
• Myelodysplastic syndromes
• Chemotherapy
• Chronic hypoxia (low blood oxygen levels)
• Carbon monoxide poisoning
• Certain cancers, including colorectal, esophageal, or liver cancer

What a Normal MCV Means

A normal MCV result can mean just that: that everything is perfectly normal. But it could also indicate a medical problem if other tests in the CBC are abnormal.

Normocytic anemia is a type of anemia in which red blood cells are of normal size and composition but are simply too few in number to deliver oxygen efficiently.

Iron deficiency anemia, anemia of chronic disease, and lead poisoning can all start as normocytic anemia but, over time, transform into microcytic anemia as more organ systems that contribute to erythropoiesis are affected.

Normocytic anemia can also occur with conditions like:

• Hemorrhage: Blood loss, seen or unseen, can lead to a rapid loss of body fluid volumes ( hypovolemia ), including a steep drop in red blood cells.
• Kidney failure: The kidneys produce a hormone called EPO essential to erythropoiesis. The loss of EPO steeply reduces the production of red blood cells.
• Aplastic anemia: This is a rare but serious condition in which bone marrow cannot produce enough new blood cells for your body to function normally.
• Leukemia: This blood cancer affects bone-forming tissues, including bone marrow and the lymphatic system. Normocytic anemia is a common consequence.
• Bone metastasis: This is the spread of cancer (often from the breast, lungs, or prostate) to the bone where it can damage bone marrow.

Summary

MCV is useful for evaluating anemia and some other medical conditions. But it is not usually looked at alone. Instead, your healthcare provider will consider MCV alongside other things in a CBC to get a complete picture. In addition to anemia, MCV outside of an expected range can suggest lead poisoning, vitamin deficiency, or liver disease.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

1. MedlinePlus. MCV (mean corpuscular volume).
2. Hsieh YP, Chang CC, Kor CT, Yang Y, Wen YK, Chiu PF. Mean corpuscular volume and mortality in patients with CKD. Clin J Am Soc Nephrol. 2017;12(2):237–244. doi:10.2215/CJN.00970116
3. American Society of Hematology. Iron-deficiency anemia.
4. Lee JY, Choi H, Park JW, Son BR, Park JH, Jang LC, Lee JG. Age-related changes in mean corpuscular volumes in patients without anaemia: An analysis of large-volume data from a single institute. J Cell Mol Med. 2022;26(12):3548–56. doi:10.1111/jcmm.17397
5. Rampon K. Anemia: microcytic anemia. FP Essent. 2023 Jul:530:12-16.
6. Nagao T, Hirokawa M. Diagnosis and treatment of macrocytic anemias in adults. J Gen Fam Med. 2017;18(5):200-204. doi:10.1002/jgf2.31
7. Sommer M. Anemia: normocytic anemia. FP Essent. 2023 Jul:530:22-33.

By Lynne Eldridge, MD
Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of “Avoiding Cancer One Day at a Time.”

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