Complete Blood Count (CBC) with Differential

Test Quick Guide

Mean corpuscular volume (MCV) is a measurement of the average size of red blood cells (RBC) in a sample of blood. RBC carry oxygen throughout the body to support the health and function of organs and tissues.

An MCV test is part of a panel of tests called the RBC indices that evaluate certain features of how RBCs function. The MCV test can help to identify if RBC are too big or too small. Changes in RBC volume can affect how oxygen is distributed throughout the body and may be a sign of a blood disorder or other health conditions.

About the Test

Purpose of the test

The purpose of the MCV test is to measure the average size of your RBC and check for signs of medical conditions such as anemia, a common blood disorder in which your body cannot carry and distribute a necessary amount of oxygen to organs and tissues.

An MCV test is performed along with several other measurements called RBC indices. These provide information about the physical features of RBC and are included as part of a complete blood count (CBC), a routine blood test. The RBC indices include:

  • Mean corpuscular volume (MCV)
  • Mean corpuscular hemoglobin (MCH)
  • Mean corpuscular hemoglobin concentration (MCHC)
  • Red cell distribution width (RDW)

During an analysis of CBC, MCV may be compared to other RBC indices to diagnose different types of anemia, a condition in which blood does not carry enough oxygen to the body.

For more information about the purposes of a CBC, see our guide to the Complete Blood Count.

What does the test measure?

The MCV test measures the average size of your RBC.

RBC can vary from normal in size to abnormally small or large. The average size is a calculation of the blood cells in a collected blood sample that describes the approximate size of RBC in your body.

When should I get an MCV test?

MCV is one of the RBC indices, measured as part of a CBC, a standard laboratory test that is performed for many reasons. A CBC may be ordered during a routine health exam as well as part of the diagnostic and follow-up testing for a wide range of conditions.

If you have symptoms of anemia, your health care provider will order a CBC and carefully compare the MCV to other tests, including other RBC indices.

Early signs and symptoms of anemia may include:

  • Feeling weak or tired more often than usual
  • Numbness and tingling in the hands and feet
  • Loss of appetite
  • Feeling irritable
  • Problems concentrating or thinking
  • Headaches

If the anemia progresses, additional signs and symptoms may include:

  • Blue color to the whites of the eyes
  • Desire to eat ice or other non-food items, including dirt
  • Pale skin color
  • Shortness of breath with mild activity or at rest
  • Mouth ulcers
  • Dizziness or lightheadedness when you stand up
  • Sore or unusually red tongue
  • Nails that break easily
  • Abnormal or increased menstrual bleeding

Finding an MCV Test

How can I get an MCV test?

MCV is included in a CBC which is most commonly conducted in a health care setting by a licensed professional. A blood draw is generally required for a CBC.

If you have any concerns about your health and feel as though an MCV test might be right for you, contact your doctor.

You can order a CBC online from Testing.com and go to a local lab for a blood draw.

Can I take the test at home?

Options are available for at-home CBC testing that include an assessment of MCV and other RBC indices. At-home CBC testing allows you to collect a sample of blood at home. That blood sample is then sent to a laboratory for analysis. It may take two to three days for the results to be available. You will be notified that results are ready to view through an online health portal or by email.

At-home CBC testing cannot be used to diagnose a disease or health condition. Rather, results should be shared with a health care provider who is familiar with your health history and current situation. Only a health care provider can interpret the values on a CBC for the purpose of assessing your health and diagnosing diseases. They may recommend repeating the CBC by traditional blood draw to confirm the results.

How much does the test cost?

The cost of a CBC, including MCV, depends on several factors, namely whether you are paying out of pocket or have health insurance. Because the CBC is commonly considered a routine test, the cost may be covered by insurance depending on your plan. However, there may still be charges related to copays and deductibles.

For specific details on expected costs for a CBC, talk to your doctor or insurance provider.

If you order a CBC from Testing.com, you’ll pay $37, which includes a blood draw at a local lab.

Taking an MCV Test

A blood sample is required for an MCV test as part of a CBC, which is ordered and conducted by a licensed health care professional. A blood sample is usually drawn from a vein inside the crook of your elbow or the top of your hand and collected in a test tube.

Before the test

There is usually no preparation required before carrying out a venous blood draw for a CBC to find the MCV unless your doctor considers it necessary.

Since the CBC is a common health assessment, it is possible that your health care provider may be drawing blood for other blood tests at the same time. Depending upon the purpose of your testing, your provider may ask you to not eat anything for a certain amount of time or give other instructions prior to your blood draw.

If there are any questions or concerns you have about any test preparation, contact your health care provider.

During the test

There are several steps that occur during a needle blood draw:

  1. In a health care setting, a licensed professional will locate the vein in your arm, hand or another part of your body from which they will draw blood.
  2. An alcohol wipe is used to clean the area of the arm where the needle will be inserted.
  3. A rubber band, called a tourniquet, is then placed around your upper arm to make the vein in your arm more visible and easier to access with a needle.
  4. The needle is placed in your vein, and a blood sample tube is then attached to the needle which automatically fills with blood. It is possible that you will feel a pinch or a little pain when the needle is inserted.
  5. After the sample vial is filled, the needle and tourniquet are removed.

After the test

Once the blood draw is over, an adhesive bandage or cotton swab will be applied to the area where the needle was inserted to prevent bleeding. You may be instructed to keep this in place for an hour or more.

Slight dizziness, lightheadedness, and bruising are all common side effects after a blood draw.

If you feel lightheaded after your blood draw, your health care provider may ask you to stay seated briefly to monitor you and ensure you are able to safely walk and/or drive.

MCV Test Results

Receiving test results

The results of an MCV and CBC test may be available within a few minutes or up to a few days after the blood sample arrives at the laboratory, depending on where your sample was collected and the equipment and procedures used to conduct the test.

A report with the test results may be shared with you through an online health portal or you may request a physical copy. If the CBC test was ordered by your health care provider, a member of your health care team will likely contact you to discuss the results.

Interpreting test results

MCV test results are interpreted by comparing your MCV to a reference range, or the set of values that the laboratory expects for a healthy person. Reference ranges are based on the results of a large sample of healthy people and are associated with the equipment and procedures of the laboratory that conducts the test.

MCV is usually reported in femtoliters (fL). The American Board of Internal Medicine lists a typical MCV reference range as 80-98 fL.

MCV levels are reported as within the reference range if they fall within the expected range for a healthy individual. If the MCV result is outside of the reference range, it may be reported as high or low.

If you have anemia or other health conditions you can have normal or abnormal MCV results. It is also possible for healthy people to have a normal or abnormal MCV result.

In patients with anemia, MCV results are categorized as follows:

  • Low MCV means that RBC are smaller than normal and may indicate microcytic anemia. This condition may be caused by iron deficiency, lead poisoning, or thalassemia, a genetic condition that causes your body to have less hemoglobin than normal.
  • Normal MCV may indicate normocytic anemia. This can occur when an individual experiences symptoms of anemia due to sudden blood loss, kidney failure, or aplastic anemia, a rare disorder where the body does not produce enough RBC.
  • High MCV means that the RBC are too large and indicates macrocytic anemia. This condition can be caused by several factors including low folate or vitamin B12 levels or chemotherapy.

MCV is usually not interpreted as an isolated measurement. Rather, it is compared to the results of your other RBC indices and CBC values, like hemoglobin and hematocrit. Your doctor will also consider any symptoms or changes in your health when interpreting these test results.

Your MCV levels may have some implications for your health. Some questions you may ask about your MCV results with your health care provider include:

  • What do my MCV levels indicate about my health?
  • Can any diagnoses be made based on my MCV results?
  • Do I need any follow-up tests based on my MCV results?
  • If my MCV test results come back abnormal, is there anything you would suggest to improve my health?

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