Mean corpuscular volume (MCV) Blood Test - An Overview

Introduction

Three main types of forming elements of blood cells include red blood cells, white blood cells, and platelets. Red blood cells provide oxygen throughout the body for organs, tissues, and cells to maintain health and function effectively.

The MCV test is counted among a group of tests called the red blood cell index that evaluates certain characteristic features of red blood cell function. The MCV test also helps determine whether the red blood cells are too large or too small. The shift in red blood cell volume affects oxygen distribution throughout the body and can signify blood-related issues like anemia, vitamin deficiencies, or other illnesses.

What Is an MCV Blood Test?

MCV (mean corpuscular volume) represents the average particle volume. The MCV blood test measures the average size of red blood cells in a blood sample. The MCV blood test is often part of a complete blood count, a routine screening test that measures various components of the blood, including red blood cells. This test shows the size of the red blood cells produced in the blood. In particular, red blood cells must be balanced and produced in adequate amounts.

Why Do I Need an MCV Blood Test?

The health care provider may order a complete blood count, including an MCV test, as part of a routine checkup or if any blood disorder manifestations are present. The symptoms include:

• Fatigue or tiredness.

• Abnormal bleeding or bruising.

• Cold extremities (hands and feet).

• Pale or lighter skin.

What Happens During an MCV Blood Test?

The blood sample is usually taken from a vein in any of the arms using a small needle. The blood will be collected into a test tube or vial. There might be a little discomfort when the needle goes in or out.

How to Prepare for the MCV Test?

There are no special preparations required for an MCV blood test. However, if the health care provider has ordered more tests on the blood sample, like the thyroid profile, the patient may be restricted from eating or drinking for a few hours before the test. The health care provider will inform the patient if there are any special precautions to follow.

Are There Any Risks to the Test?

There is minimal risk associated with this blood test. The patient may have minimal pain or bruise at the needle's location, but most symptoms quickly disappear.

What Do the Results of an MCV Test Mean?

If the results show that the red blood cells are smaller than average, it may indicate:

• Iron deficiency anemia or other types of anemia.

  • Anemia is said to be present when the blood contains a lower average amount of red blood cells. Iron deficiency anemia is the most prevalent form of anemia.

• Thalassemia is an inherited disorder that can cause severe anemia.

If the results show that the red blood cells are larger than average, it may indicate the following:

• A vitamin B12 deficiency.

• Folic acid deficiency (another type of vitamin B).

• Liver diseases.

• Hypothyroidism.

If the MCV levels are not within the normal range, it does not necessarily mean that the patient has a medical problem needing treatment. Diet, activity level, medicines, a woman's menstrual cycle, and other considerations can affect the results. Talk to the health care professional to get the results interpreted.

Is There Anything Else to Know About an MCV Blood Test?

Suppose the health care provider suspects the patient has anemia or another blood disorder. In that case, they may order additional tests of the red blood cells, including a red blood cell count and hemoglobin measurements.

What Does an Abnormal MCV Level Mean?

Remember that the level of red blood cells should be within the normal range to perform its function correctly. MCV levels will also determine if the patient is anemic. But aside from that, it would also interpret the reason for the abnormal red blood cell count and how to proceed with the treatment.

There are two abnormal findings seen in an MCV blood test. First, the count could be either too high or too low. A drop in the red blood cell volume is often associated with microcytosis (anemia due to smaller red blood cells). A low MCV would often result in tiredness and fatigue. These results are because the amount of oxygen delivered to the cells is too low as well. The opposite of this is macrocytosis. When too many red blood cells are generated, they are more prone to break on the tiny capillaries and might cause severe damage.

The MCV blood test value is measured in femtoliter and has a normal range of 80 to 100 fL. The normal range of MCV count in different age groups is as follows:

• Newborn - 106 fL.

• Three months of age - 95 fL.

• One-year-old - 70 to 86 fL.

• Three to six years - 73 to 89 fL.

• 10 to 12 years - 77 to 91 fL.

High MCV Means -

Different things or conditions may cause a high MCV. Knowing these are essential to avoid developing an increased red blood cell count, which include -

• Decreased Vitamin B12 Intake - Vitamin B12 is one of the essential components required to form red blood cells and DNA. Vitamin B12 deficiency may occur due to excessive alcohol consumption and poor diet. If the doctor identifies that the patient has a little amount of vitamin B12 in the body, they are usually advised to take supplements to maintain the balance.

• Deficiency in Folic Acid - The vitamin folic acid is also imperative in producing the appropriate red blood cells. Therefore, if the test indicates a low folic acid level, the patient may take the prescribed medicine to recover. One of these would be the replacement therapy of a 5 mg folic acid tablet to be consumed daily for at least four months.

• Increased Alcohol Intake - If a person consumes excess alcohol than the acceptable quantity, it will damage the storage of vitamin B12. This would cause a high MCV.

Low MCV Means -

A low MCV count is more common than a high MCV. Therefore, knowing its causes is essential to providing the correct treatment, such as -

• Prolonged Blood Loss - This condition usually arises in women with heavy bleeding during menstruation. This condition would also result in low iron levels, thus affecting the MCV count. If this happens often, prescribed pills or medicine should be asked by the doctor to remedy the problem.

• Anemia - One of the significant components of hemoglobin is iron, so when a person has a meager iron level, the decrease in MCV value is inevitable. If anemia is confirmed with the laboratory tests, the doctor recommends an iron-rich diet to enhance the iron intake and may even prescribe supplements as an adjunct therapy.

• Thalassemia - Unfortunately, this diagnosis is inherited and cannot be avoided once it is a part of your genes. The body cannot produce the correct amount of hemoglobin in this condition. The only treatment option available to treat thalassemia is bone marrow transplantation.

Conclusion:

MCV value helps diagnose anemia and other medical illnesses, particularly blood disorders. The healthcare provider will consider MCV alongside other things in a CBC to get a complete picture. In addition to anemia, MCV outside of the expected range can suggest poisoning, vitamin deficiency, and liver disease. MCV can also help determine a prognosis for certain cancers and chronic kidney disease. In addition, it may be used to evaluate cognitive function in older adults.