Mean corpuscular volume (abbreviated as MCV) is the average amount of space occupied by each red blood cell. Red blood cells help carry oxygen in the blood.
An MCV Blood Test is one component of the CBC Blood Test that measures the number and the different types of cells in your blood.
Specifically, it is actually a measure of the average VOLUME of Red Blood Cells that are also called Erythrocytes. The word MCV stands for Mean Corpuscle Volume- as red blood cells are also sometimes referred to as corpuscles.
The normal range is between 80 to 100 fl.(there are ALWAYS slight variations between different labs) and the two possibilities for abnormal levels are:
Macrocytic Anemia: When the number is BIGGER than it should be, this means that the cell is LARGER than normal. This is a condition called Macrocytic Anemia or Macrocytosis.
Microcytic Anemia: When the number is SMALLER than normal, the cell is too SMALL and this is a condition called Microcytic Anemia or Microcytosis.
While the term ‘anemia’ by itself is a well known condition that usually means too few red blood cells, low iron, or too little hemoglobin; microcytic and macrocytic anemia mean something different.
Macrocytic Anemia or Macrocytosis
When the MCV blood test has a HIGH number- even slightly- this means that the blood cells are too large and is called macrocytosis or Macrocytic Anemia.
This SHOULD trigger a further workup from your doctor to find out WHY they are too large, but mild macrocytosis is very often overlooked as not being important.
But Macrocytic Anemia IS an important finding and could mean a few different things that are VERY significant to your health.
The first and most obvious thing that your doctor should suspect- especially if you have fatigue- is Vitamin B12 Deficiency.
Vitamin B12 Deficiency affects MILLIONS of people and very often goes undiagnosed. When macrocytosis occurs as a Sign of Vitamin B12 Deficiency, you have most likely already had Vitamin B12 deficiency for at LEAST 2 years- the amount of time that it takes to noticeably affect the red blood cells.
This can be caused by poor diet, Vitamin B12 Malabsorption, and sometime from drugs, such as the:
- Side Effects of Metformin or
- Nitrous Oxide Side Effects
How is the Mean Corpuscular Volume Calculated?
The MCV is calculated by dividing the total number of packed red blood cells (also known as hematocrit) by the total number of red blood cells.
The resulting number is then multiplied by 10. The red blood cells get packed together when they are spun around at high speeds in a device called a centrifuge.
What is the Normal Level of the Mean Corpuscular Volume?
The normal MCV level for people over age 18 is between 78 and 98 cubic micrometers (abbreviated um3). See the next section for a description of cubic micrometers.
The normal MCV level for newborns is between 95 and 121 um3. Between 6 months to 2 years, the average range is 70 to 86 um3.
For boys ages 12 to 18 years, the average range is 78 to 98 um3. For girls ages 12 to 18 years, the average range is 78 to 102.
It is important to keep in mind that the ranges mentioned above will be different depending on the machine used to do the blood test. Always use the normal range printed on the lab report to decide what range is normal.
Why is Your MCV Blood Test Abnormal?
Whether your MCV is too high OR too low, there should be a ‘good reason’ for it to be abnormal.
You should not allow your doctor to say that it is not significant, because- except in the case of menstruation- it is almost always very significant.
If you have ANY chronic health problem, then finding out WHY you have an abnormal MCV test could be the key to uncovering the underlying CAUSE of your health problems.
Whether you need further testing of your Vitamin B12 Level and other vitamin testing, such as your Vitamin D Level, or Testing for Gluten Sensitivity, you should get your doctor to answer the question of WHY your MCV Blood Test is abnormal.
If you are otherwise extremely healthy, a vague answer and another test a few months later is probably sufficient.
But for those of you suffering from chronic health problems, use this opportunity to take control of your own health and perhaps do a trial of Methylcobalamin Vitamin B12 Supplements or try out a Gluten Free Diet and see how you feel.
Few doctors will ever address issues like an abnormal MCV Blood Test, for most of us, we have to learn to be our own doctors and find solutions that work for us.
Keep reading to find out more about Vitamin B12 Malabsorption.
What Can Cause The Mean Corpuscular Volume To be Too High?
There are many possible reasons why the MCV level can be too high. One reason is because of liver disease.
The liver is the largest organ in the body and is responsible for filtering (removing) harmful chemical substances, producing important chemicals for the body, and other important functions.
Cirrhosis (a type of disease that destroys the liver) can cause high MCV levels. Another cause of a high MCV level is alcohol abuse.
Hypothyroidism can cause the MCV level to be too high. Hypothyroidism is a condition in which the thyroid gland is underactive.
The thyroid gland is a butterfly-shaped organ located in front of the neck that produces a natural chemical known as hormones that affect virtually every cell in the body and many functions such as disease fighting, heart rate, energy level, and skin condition.
Myxedema, the most severe form of hypothyroidism, can cause high MCV levels as well.
Another condition that can cause an increased MCV level is myelofibrosis, in which the normal bone marrow (a type of tissue inside of the bones) is replaced by fibrous tissue (the connective tissue of the body).
Yet another condition that can cause an increased MCV level is marrow aplasia, in which bone marrow is not present in the opening inside of bones where it is normally found.
Reticulocytosis can cause an increased MCV level as well. Reticulocytosis is a condition in which there is an increase in the number of reticulocytes (a type of red blood cell) in the blood.
A cell is the smallest, most basic unit of life, that is capable of existing by itself. Red blood cells help carry oxygen in the blood.
Having too little vitamin B12 or folic acid (a type of vitamin) in the body can also cause the MCV level to increase.
A vitamin is one of a group of substances made up partly of carbon (an element) that are essential in small amounts for normal bodily functioning and chemical processes in the body to take place.
What Can Cause the Mean Corpuscular Volume To be Too Low?
There are many possible reasons why the MCV level can be too low. One reason is because of lead poisoning. Long-lasting kidney failure can also cause the MCV level to be too low.
The kidneys are two organs located on each side of the spine, behind the stomach. The kidneys filter (remove) wastes from the blood.
A long-term decrease of iron in the body can cause low MCV levels. Amemia can also cause a low MCV level. Anemia is a condition in which there is an abnormally low amount of hemoglobin in the blood.
Hemoglobin is substance present in red blood cells that help carry oxygen to cells in the body.
Hemoglobinopathy, which is a group of disorders characterized by changes in the structure of hemoglobin, can also cause a low MCV level.
Why Is it Called Mean Corpuscular Volume?
Another word for the average of something is the mean. The word “mean” comes from the Middle English word “mene” meaning “in the middle.”
Corpuscular comes from the Latin word “corpusculum” meaning “little body.” In this case, the red blood cells are the little bodies.
Volume refers to the amount of space occupied by something. Volume comes from the Latin word “volumen” meaning “something rolled up.”
In sum, now you can see why the mean corpuscular volume means the average amount of space occupied by each red blood cell.