what is mcv in blood test


Blood tests are an essential tool in diagnosing and monitoring various health conditions. One such test is the Mean Corpuscular Volume (MCV) test, which measures the size of red blood cells. Understanding MCV results can provide valuable insights into a person’s overall health and help identify potential underlying medical issues. In this article, we will explore what MCV is, its normal range, and the causes and interpretation of high and low MCV values.

Understanding MCV

MCV, or Mean Corpuscular Volume, is a measurement that determines the average size of red blood cells in a given blood sample. Red blood cells play a vital role in transporting oxygen throughout the body. By analyzing the size of these cells, healthcare professionals can gain valuable information about various blood disorders and deficiencies.

Normal MCV Range

The normal range for MCV typically falls between 80 and 100 femtoliters (fL). MCV values outside this range may indicate an underlying health issue that requires further investigation.

Causes of High MCV

When MCV levels exceed the normal range, it is known as high MCV. Several factors can contribute to high MCV values, including:

1. Vitamin B12 Deficiency

A deficiency in vitamin B12 can lead to high MCV levels. Vitamin B12 is crucial for the production of healthy red blood cells. Insufficient levels of this vitamin can cause red blood cells to enlarge, resulting in an elevated MCV.

2. Folate Deficiency

Similar to vitamin B12 deficiency, a lack of folate, also known as vitamin B9, can lead to high MCV levels. Folate plays a vital role in red blood cell production and DNA synthesis. Insufficient folate levels can cause red blood cells to grow larger, leading to an increased MCV.

3. Liver Disease

Liver diseases, such as alcoholic liver disease or cirrhosis, can affect the size of red blood cells, resulting in high MCV values. The liver plays a crucial role in producing and regulating substances necessary for proper blood cell formation. Impaired liver function can disrupt this process and contribute to elevated MCV levels.

4. Alcoholism

Excessive alcohol consumption can also cause high MCV levels. Chronic alcohol abuse affects the bone marrow’s ability to produce healthy red blood cells, leading to an increase in MCV values.

Causes of Low MCV

Low MCV values occur when red blood cells are smaller than the normal range. Several factors can contribute to low MCV levels, including:

1. Iron Deficiency Anemia

Iron deficiency anemia is a common cause of low MCV values. Insufficient iron levels affect the production of hemoglobin, the protein responsible for carrying oxygen in red blood cells. Without adequate iron, red blood cells become smaller, resulting in a decreased MCV.

2. Thalassemia

Thalassemia is an inherited blood disorder characterized by the abnormal synthesis of hemoglobin. It can cause red blood cells to be smaller and paler, leading to a low MCV. There are different types of thalassemia, ranging from mild to severe forms, each affecting the MCV levels differently.

3. Chronic Disease

Chronic diseases, such as chronic kidney disease or rheumatoid arthritis, can contribute to low MCV values. These conditions can interfere with red blood cell production and result in smaller-sized cells and a decreased MCV.

4. Lead Poisoning

Exposure to lead, either through contaminated water, paint, or certain occupations, can affect the production of red blood cells. Lead poisoning can lead to decreased MCV levels as it disrupts the normal development of these cells.

Interpretation of MCV Results

Interpreting MCV results requires considering various factors, including the individual’s medical history, symptoms, and other blood test results. High MCV values may indicate conditions such as vitamin deficiencies, liver disease, or alcoholism, while low MCV values may suggest iron deficiency anemia, thalassemia, or chronic diseases.

It’s essential to consult a healthcare professional to evaluate MCV values accurately and determine the underlying cause. They will consider the complete clinical picture and may recommend additional tests to confirm a diagnosis or guide further treatment.


The Mean Corpuscular Volume (MCV) test provides valuable insights into a person’s blood health and helps identify potential underlying conditions. Understanding the significance of MCV values, whether high or low, can aid in the diagnosis and management of various blood disorders. It is crucial to consult with a healthcare professional to interpret MCV results accurately and receive appropriate guidance and treatment.


1. Can MCV levels change over time?

Yes, MCV levels can change depending on various factors such as nutritional status, medical conditions, or treatment. Regular monitoring of MCV values can help track any changes and guide healthcare decisions.

2. Are high MCV values always a cause for concern?

Not necessarily. While high MCV values may indicate certain health conditions, it is essential to consider other factors and consult with a healthcare professional for an accurate diagnosis.

3. Can MCV values be influenced by medications?

Yes, certain medications, such as chemotherapy drugs or anticonvulsants, can affect MCV levels. If you are taking any medications, it’s important to discuss their potential impact on MCV values with your healthcare provider.

4. Can MCV levels indicate specific types of anemia?

Yes, MCV values can provide clues about the type of anemia present. High MCV values may suggest vitamin deficiency anemia, while low MCV values can be associated with conditions like iron deficiency anemia or thalassemia.

5. Is MCV the only test used to diagnose blood disorders?

No, MCV is just one component of a comprehensive blood panel. Additional tests, such as hemoglobin, hematocrit, and peripheral blood smear, may be necessary to confirm a diagnosis and provide a complete assessment of blood health.

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