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What Does It Mean If Your MCV Blood Test Is High?

Medically Approved by Dr. Edward Salko
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a blood sample for confirming mcv high blood test

The information in this article is not intended to replace professional medical advice, diagnosis, or treatment. Instead, consult your physician or any licensed healthcare providers if you have medical questions to get personalized answers.

When you have high mean corpuscular volume or MCV in your blood test, it means your red blood cells (RBC) are larger than normal and disrupt blood functions. To lower your MCV levels, your healthcare provider will likely recommend dietary changes and vitamin supplementation on top of the prescribed medications. Find out more about what conditions cause high MCV and what it means for your health. 

What Causes High MCV Levels in a Blood Test?

Getting a high MCV level (above 100 fl) in your blood test typically suggests macrocytic anemia. Macrocytic anemia is a blood disorder characterized by abnormally large RBCs and can be linked to several health conditions, including intake of specific drugs. That said, having high MCV levels can be due to the following reasons:

  1. Vitamin B12 or B9 Deficiency

Lack of vitamin B12 (cobalamin) and vitamin B9 (folate) causes deformities and size disparity in the RBCs. After all, both vitamins are involved in producing red blood cells in the bone marrow. 

If you have high MCV levels, it may be time to increase your uptake of foods rich in vitamins B12 and B9 or include supplementation as advised by your healthcare provider.

Did You Know? Folate deficiency remains the most common cause of high MCV. Even the diseases associated with elevated MCV are linked to the malabsorption of vitamin B12 and B9. In that sense, you can avoid having high MCV in your blood test when you ensure the inclusion of the said vitamins in your diet. 
  1. Autoimmune Gastritis

Elevated MCV is also observed in patients with autoimmune gastritis. It is a chronic disease characterized by the inflammation of the stomach’s upper section containing the body and fundus. 

The immune system mistakenly attacks the cells in the stomach lining. Autoimmune gastritis leads to folate deficiency, causing macrocytic anemia or macrocytosis–which translates to high MCV levels in the blood test. 

Since it’s an autoimmune form of gastritis, the true cause of the condition remains undetermined. You’ll likely develop autoimmune gastritis if someone in your family already has the disorder. 

Man experiencing symptoms of autoimmune gastritis

Inflammation in the stomach impacts folate absorption, leading to high MCV.

  1. Hypothyroidism

Individuals with thyroid problems can get high levels of MCV in their CBC. This is because thyroid hormones stimulate the production of RBCs. If you have hypothyroidism (an inactive thyroid gland), for example, your red blood cells will have irregular sizes due to abnormal maturation. 

Did You Know: Hypothyroidism leads to lower-than-normal thyroid hormones. This condition can be traced back to health issues, such as iron deficiency, thyroiditis, and problems with the pituitary gland.    
a woman trying to feel any abnormality in her thyroid gland

Increased MCV levels are noted among individuals with hypothyroidism. 

  1. Liver Disease

Liver disease can change the structure and composition of your RBCs. For example, if you have liver disease, you’re most likely to have increased cholesterol deposition1 in your RBCs, which leads to macrocytosis. The elevated phospholipids are linked to the impaired ability of the liver to regulate cholesterols. 

In addition, elevated MCV levels also suggest the severity of liver damage2, as shown in a study conducted among patients with hepatitis B infection. By extension, it indicates the mortality risk of the patient in relation to the hepatic disorder. 

  1. Chronic Alcoholism

Alcohol abuse impedes bone marrow function, the site of red blood cell production. As a result, RBCs can be low in count or unusually large, which elevates your MCV level. 

Plus, the toxicity of alcohol also alters the lipid structure of the red blood cells, which, in turn, leads to macrocytosis. Nonetheless, abstaining from alcohol gradually can help correct the high MCV levels. 

A man who consumed too much alcohol with high MCV levels

Overconsumption of alcohol can lead to elevated MCV levels.

  1. Medications  

Drugs that interrupt folate absorption contribute to macrocytic anemia. These include chemotherapy drugs, antiretroviral medications, and antiseizure drugs.   

For this reason, it’s crucial to talk to your doctor about your concerns and questions regarding the high MCV levels in your lab work. 

How an MCV Blood Test Works

A mean corpuscular volume (MCV) blood test measures the size of your red blood cells (RBCs) to help diagnose anemia, folate deficiency, liver disease, hypothyroidism, and chronic hypoxia. It’s included in the complete blood count (CBC)

The MCV lab test goes hand-in-hand with other tests that determine the characteristics of RBC, such as the following:

  • Mean corpuscular hemoglobin (MCH) measures the average amount of hemoglobin (the protein that carries oxygen) in the RBC. 
  • Mean corpuscular hemoglobin concentration (MCHC) screens for the concentration level of hemoglobin in an RBC. 
  • Red cell distribution width (RDW) compares the sizes of RBCs and determines significant differences. 

By looking into all these indices, doctors can diagnose different types of anemia and other health conditions influencing hemoglobin production and RBC size. 

How Is the Test Done?

An MCV lab test requires a blood sample drawn from the veins. That’s why it has to be performed in a trusted laboratory. No special preparation is necessary, especially if it’s part of a CBC test. But your doctor may request you to fast for 8 hours, depending on the test’s purpose. 

Blood being drawn for MCV blood test

A blood sample extracted through venipuncture is needed for an MCV lab test

MCV Blood Test Range

The normal MCV blood test range is from 80 to 100 femtoliters (fl)3. If your test results indicate above the upper limit of the range (>100 fl), your RBCs may be larger than normal, suggesting macrocytic anemia. On the other hand, if it is below 80 fl or the lower limit, you’re likely to have microcytic anemia. 

When Should You Take the MCV Blood Test?

Doctors often recommend the MCV blood test when symptoms of anemia, specifically macrocytic and microcytic anemia (RBCs are smaller than the average size), appear. These symptoms include:

  • Shortness of breath
  • Fatigue or weakness 
  • Irregular heartbeat (arrhythmia)
  • Numbness and tingling in the extremities 
  • Trouble concentrating
  • Appetite loss
  • Irritability

Your doctor may also order this blood test as part of your wellness checkup. But often, it’s a response to verify symptoms of the conditions mentioned above. 

Treatment for High MCV

The right treatment for high MCV should respond to the exact cause of the condition. If the elevated MCV is due to an underlying disease, your doctor will prepare a treatment plan specific to the health condition. 

Frequently Asked Questions

Does high MCV mean cancer?

High MCV levels in a blood test do not automatically mean cancer. Macrocytosis is linked to different disorders, which include cancer. Hence, if you have elevated MCV, you’ll likely have to take other lab tests to properly diagnose the cause of the condition. 

What cancers cause high MCV levels?

Liver cancer is the most associated type of cancer with high MCV levels since liver dysfunctions lead to more fats adhering to the membrane of the red blood cells. This, in turn, increases their surface levels. Other cancers, such as colorectal and esophageal cancers, could also lead to macrocytic anemia.  

What does high MCV and MCH mean?

If your MCV and MCH levels are high, it’s a clear sign of macrocytic anemia. MCH measures the average concentration of hemoglobin in the red blood cells. High MCH correlates with the large size of the RBC, as measured by the MCV blood test. You’re likely to have elevated MCV and MCH if you have folate deficiency, thyroid problems, and liver disease.

How should I lower my MCV levels?

Lowering your MCV levels requires better understanding and/or diagnosing the cause of the macrocytosis. But on top of medical treatment, you can help normalize high MCV by adjusting your diet accordingly, vitamin supplementation, and regulating alcohol intake. 

How Long Does It Take for MCV To Return to Normal?

When the proper treatment is set, you can expect to have your high MCV levels fixed within 2 to 4 months. For example, if you withdraw from alcohol consumption and increase your dietary intake of folate-rich foods, your bone marrow will produce normal-sized RBCs, provided that there are no other factors for the condition. 

The Bottom Line

The CBC test provides information about your blood, including your red blood cell structure and count. As it often includes the MCV test, it’s best to understand the results and what it means for your health to have high MCV levels. For a more personalized assessment and treatment, we recommend consulting your doctor promptly. 


1 Yang, J., Yan, B., Yang, L., Li, H., Fan, Y., Zhu, F., Zheng, J., & Ma, X. (2018). Macrocytic anemia is associated with the severity of liver impairment in patients with hepatitis B virus-related decompensated cirrhosis: A retrospective cross-sectional study. BMC Gastroenterology, 18.

2 Yang, J., Yan, B., Yang, L. et al. Macrocytic anemia is associated with the severity of liver impairment in patients with hepatitis B virus-related decompensated cirrhosis: a retrospective cross-sectional study. BMC Gastroenterol 18, 161 (2018).

3 Maner BS, Moosavi L. Mean Corpuscular Volume. [Updated 2022 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:

Get fast and accurate MCV test results with our Complete Blood Count (CBC) Test

When it comes to blood tests, CBC labs measure the level of red and white blood cells as well as platelets. The specific breakdown of measurements includes:

Mean corpuscular volume (MCV)
Red blood cell count
White blood cell count

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