Table of contents
Blood MCV Test, Mean Corpuscular Volume, Mean erythrocyte volume test
MCV in hemogram tests refers to the mean volume of erythrocytes as the mean body volume. Erythrocytes take the oxygen the body needs from the lungs, store it and deliver it to the tissues. The size of erythrocytes affects their storage capacity. Very small erythrocytes have a lower oxygen storage capacity. Oxygen carrying capacity of large erythrocytes may decrease due to other abnormalities they carry or there may be problems in oxygen delivery. It is possible for large erythrocytes to cause anemia because of their short life span and their inability to reach small capillaries. In short, the size of erythrocytes is very important in the detection of anemia, vitamin deficiencies or some hematological diseases.
MCV is usually part of a complete blood count test. Many different features are also tested and evaluated together. In patients with complaints such as shortness of breath, weakness or fatigue, headache, dizziness or arrhythmia, a complete blood count is performed and the MCV value is calculated as part of this test.
Erythrocyte volume is expressed in femtoliter (fL). Erythrocytes are divided into three according to their volume:
- microcyte
- normocyte (80-100 fL)
- macrocyte
If any abnormality is detected in the examination of the size of the erythrocytes, the hemoglobin carrying capacity of the erythrocytes or other blood tests are evaluated together. For example, other data such as RDW, Hgb, Hct, MCHC are also used in the evaluation. Peripheral smear, bone marrow biopsy or other techniques may be used in cases requiring further investigation.
The most common causes of low MCV are:
- Homogeneous microcytic anemia
- Thalassemia
- Chronic diseases
- Heterogeneous microcytic anemia
- Iron deficiency
- Copper deficiency
- Chronic alcoholism
- Use of isoniazid
- Vitamin B6 deficiency
- S Beta thalassemia
- Hemoglobin H disease
- Erythrocyte breakdown (Sideroblastic anemia)
- Myeloproliferative disorders
- Anemia due to nutritional disorders
A normal MCV value may not indicate that everything is normal. Because in many diseases, anemia or other symptoms can be seen even though the MCV value is normal. Anemia with low MCv value suggests colon cancers in men and postmenopausal women over 50 years of age. This is a problem that deserves special attention.
Anemias and conditions with a normal MCV value:
- Homogeneous normocytic anemia
- Chronic diseases
- Chronic liver disease
- Chemotherapy
- nonanemic hemoglobinopathy
- Chronic myelocytic leukemia
- Bleeding
- Hereditary spherocytosis
- Heterogeneous normocytic anemia
- Early stage of iron deficiency anemia
- Early stage of folic acid deficiency anemia
- Hemoglobinopathies (SS, CC)
- Myelofibrosis
- Sideroblastic anemia
- Anemia due to nutritional disorders
Causes of increased MCV value:
- Homogeneous macrocytic anemia
- Aplastic anemia
- Diamond-Blackfan anemia
- Preleukemia
- Hypothyroidism
- Heterogeneous macrocytic anemia
- Folic acid deficiency anemia
- Vitamin B12 deficiency (Megaloblastic anemia)
- Immune hemolytic anemia
- Presence of cold agglutinin
- Chronic alcoholism
- Anemia due to nutritional disorders
Abnormal MCV values may not always be a sign of disease. Diet, physical activities, medications, menstrual period or laboratory quality may affect test results.