MCV is one of the parameters of complete blood count. It provides information about the size of red blood cells known as erythrocytes. Red blood cells are cells responsible for oxygen transport to tissues. Normal values for MCV: Adult, elderly, and children: 80-95 fl, in newborn infants: 96-108 fl.
MCV can be normal, low, or high. All of them mean different. It basically provides information about the type of MCV anemia (anemia). Low MCV indicates erythrocytes are smaller than normal (microcytosis), high MCV indicates that erythrocytes are larger than normal (macrocytosis). In all cases, MCV is not used alone. It is evaluated together with the MCHC and RDW values.
MCV formula: MCV = hematocrit (percent) x 10 / red blood cell count (million / mm3 blood). The devices make this measurement automatically, so physicians do not calculate every time.
What does low MCV indicate?
If the MCV is below 80 fl, there is a low MCV. It suggests types of anemia, called microcytic anemia, in which red blood cells are smaller than normal. The most common symptoms in these patients are Fatigue, weakness, loss of endurance, shortness of breath, dizziness, pale skin.
The most common types of microcytic anemia are:
- Iron deficiency anemia: It is the most common type of microcytic anemia. Malnutrition, rapid growth, chronic blood loss, prolonged menstrual bleeding, celiac disease, and helicobacter infection can cause this condition. In iron deficiency anemia, Hb, serum iron is low and serum iron-binding capacity is high, as well as low serum MCV. Iron deficiency is very common in children and pregnant women. Symptoms are pallor, fatigue, loss of appetite, chills, sleep problems, soil eating, iron licking, dry and cracked lips, inflammation of the tongue, and structural changes in nails with pallor.
- Thalassemia (Mediterranean anemia): It is a genetic type of anemia. It is more common in some geographical regions and races. It is divided into two as thalassemia carrier and real disease. Hb and MCV in the blood are low in patients with thalassemia. Serum iron can be normal or low. Real patients present very early with very low blood values. Thalassemia carrier is often confused with iron deficiency. The definitive diagnosis is made by a test called hemoglobin electrophoresis.
- Lead poisoning or exposure to high levels of lead: It is seen in people working with lead-containing paints and chemicals, people living in areas with high air pollution, miners, auto repair shops, and ceramic workshops. MCV is low. In this state, it can be confused with iron deficiency. It gives typical symptoms in gums and long bones. It can cause fatigue and encephalopathy in children.
- Chronic disease anemia: Diseases such as Crohn’s disease, kidney disease, diabetes, autoimmune diseases, rheumatoid arthritis, tuberculosis, AIDS, endocarditis, and cancers can cause microcytic anemia.
- Sideroblastic anemia: It is a form of anemia that occurs as a result of gene mutations. Iron accumulates in red blood cells. MCV is low.
Other causes are copper deficiency, chronic alcohol use, drug use.
What does the MCV height indicate?
Indicates cases where MCV is above 100 fl. Erythrocytes are larger than normal and hemoglobin is low. This condition is called macrocytic anemia. Macrocytic anemias are generally classified as either megaloblastic or non-megaloblastic anemia. Megaloblastic anemia is caused by a deficiency or impaired use of vitamin B12 and/or folate, while non-megaloblastic macrocytic anemia is caused by myelodysplastic syndrome (MDS), liver dysfunction, alcoholism, hypothyroidism, certain medications, and less commonly hereditary disorders.
- Vitamin B12 deficiency: Vitamin B12 deficiency is the most common cause of megaloblastic anemia. It is common in vegetarians, malnourished people, after gastric surgery, intrinsic factor deficiency in the stomach, and those who frequently follow the wrong diet. Signs and symptoms caused by megaloblastic anemia due to vitamin B12 deficiency are fatigue, headache, palpitations, and shortness of breath. There may be neurological symptoms such as a lack of feeling. In addition, neurological symptoms such as dysesthesia and hypoesthesia can be observed. Vitamin B12 deficiency does not necessarily lead to anemia and macrocytosis. Painful tongue and gray hair are among other symptoms. Pernicious anemia is a type of anemia seen in B12 deficiency. It is linked to stomach upset.
- Folic acid deficiency: Folic acid is found in green vegetables and animal products such as the liver. The recommended amount of folic acid for adults is 240 μg per day, and about 400 μg of folate intake per day is required for pregnant or breastfeeding women. Folic acid deficiency is common in malnourished patients, patients with alcoholism problems, patients with intestinal absorption defects called malabsorption, pregnant women, breastfeeding patients, hemolysis cases with blood breakdown, patients using methotrexate, trimethoprim, and phenytoin. Patients are treated with oral folic acid medications. In folic acid deficiency, hemoglobin is low and MCV is high.
- Myelodysplastic Syndrome: It is a disease that occurs as a result of chromosomal abnormalities. Patients may experience anemia, bleeding due to thrombocytopenia, and infection or fever due to neutropenia. In complete blood count, all blood cells are detected as low. Leukemia can be seen later in these patients.
- Alcoholism: It is among the causes of macrocytic anemia with high MCV. Alcohol consumption over 80 grams per day has a negative effect on blood production.
- Hypothyroidism: The thyroid hormone is involved in the production of red blood cells. In its deficiency, erythrocyte production decreases. Anemia can be in the form of normocytic (normal size blood cells) or macrocytic (large blood cells).
- Medications: Many drugs can interfere with B12 and folic acid absorption, leading to macrocytic anemia. As an example, we can show cancer drugs, malaria drugs, epilepsy drugs, metformin used in diabetics, and some antiviral drugs.
- Liver disease: Accumulation of cholesterol in the membrane of erythrocytes can cause this condition. Development of B12 and folic acid deficiency in advanced liver diseases may cause macrocytic anemia. Another reason is hemolytic anemia in liver diseases. Medicines used in liver disease can cause macrocytic anemia.
Normal MCV (80-100 fl)
Normal MCV indicates that red blood cells are normal in size. You may have normal MCV and also be anemic. This is called normocytic anemia. Causes of normocytic anemia: Sudden and significant blood loss, prosthetic heart valve, chronic disease such as a tumor, kidney disease or endocrine disease, aplastic anemia, and blood infection.
How is low MCV treated?
If there is an iron deficiency, iron drugs and vitamin C are given. This treatment can take up to 2-3 months. Then, complete blood count and serum iron are checked. If there is excessive bleeding due to menstrual disorder, hormone drugs are used. If microcytic anemia develops due to chronic disease, the underlying disease is treated. Dimercaprol and EDTA are used if there is lead poisoning. If there is microcytosis due to copper deficiency, copper is given. In chronic alcoholism, the patient is taken to alcohol treatment. Severe thalassemia patients are treated with regular blood transfusions. Treatment is often not required for thalassemia carriers. Helicobacter infection is treated with appropriate antibiotics.
How is high MCV treated?
In macrocytic anemia with high MCV, treatment is performed according to the cause. If serum B 12 and folic acid levels are low, B 12 and folic acid are used. B 12 can be administered orally or intramuscularly. Folic acid treatment is in the form of oral medication. Alcohol should be stopped immediately if it is due to chronic alcoholism.
In MCV normal types of anemia, the underlying disease is determined and appropriate treatment is arranged.
If you or your relatives have low/high MCV, apply to the nearest health institution for detailed evaluation. We wish you healthy days.
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