Mean Corpuscular Volume (MCV)

What sample is needed for Mean Corpuscular Volume (MCV)?

1. The best sample is EDTA blood.
2. Stable for 6 hours at 25 °C  and 24 hours at 4 °C.
3. Fetal blood is collected percutaneously from the umbilical area.

What are the indications for Mean Corpuscular Volume (MCV)?

1. This is one of the blood indices.
2. This is done to classify and diagnose anemia.
3. It is a useful screening test for occult alcoholism.

How would you define Mean Corpuscular Volume (MCV)?

• It represents the average RBC volume, ranging from 82 to 98 fL (femtoliters).
• Mean Corpuscular Volume (MCV) is calculated manually as hematocrit divided by the RBC count.
• It can be measured directly by the automated instrument.
• MCV indicates the volume occupied by a single RBC and is measured in cubic micrometers.
  1. Cubic micrometer = femtoliter ( fL ).

What are the facts about Mean Corpuscular Volume (MCV)?

1. MCV measures the effect of average RBC size on hematocrit.
2. Mean Corpuscular Volume (MCV) measures a single RBC’s average volume or size.
3. If the average size of RBCs increases, the same number of RBCs will have a slightly larger cell mass and a slightly higher hematocrit. The opposite occurs if the average RBC size is smaller than normal.
4. MCV helps to classify various anemias.
5. Macrocytic RBC:
   1. When the RBC size is larger than normal, more than 100 fL.
6. Microcytic RBC:
   • When the RBC size is smaller than normal, it is less than 82 fL.
7. It is considered that the most common cause of macrocytosis is alcoholism with or without cirrhosis.

What is the formula to calculate MCV?

What is the normal Mean Corpuscular Volume (MCV)?

Source 1

Source 2

• Adult = 80 to 95 fL.
• Newborn = 96 to 108 fL

Another source

• Both sexes = 80 to 100 fL
• Heavy smoking  increases the MCV by as much as 3 fL

What are the causes of increased Mean Corpuscular Volume (MCV)?

Macrocytic anemia causes are:

1. B12 or folic acid deficiency :
   1. Decreased ingestion.
      1. Lacking animal protein.
      2. Vegetarians.
   2. Impaired absorption.
      1. Intrinsic factor deficiency.
      2. Abnormal intrinsic factor molecule.
      3. Patient with partial or total gastrectomy.
      4. Ileal resection.
      5. Sprue.
      6. Celiac disease.
      7. Intestinal lymphoma.
      8. Drug-induced malabsorption.
2. Parasitic infestation.
   1. Diphyllobothrium latum.
   2. Infected diverticula.
   3. Blind loop.
3. Increased requirement.
   1. Pregnancy.
   2. Malignancies.
   3. Hyperthyroidism.
   4. Chronic pancreatic disease.

What are the causes of decreased Mean Corpuscular Volume (MCV)?

Microcytic anemias are seen in:

1. Iron metabolism-related.
   1. Iron deficiency anemia.
   2. Decreased dietary intake.
   3. Malabsorption.
   4. Increased iron loss.
   5. Increased body requirements for iron.
   6. Congenital hypochromic microcytic anemia.
   7. Anemia of chronic disease.
2. A defect in heme synthesis.
   1. Idiopathic refractory sideroblastic anemia.
   2. Acquired sideroblastic anemia.
   3. Hereditary sideroblastic anemia.
   4. Autosomal anemia ( X chromosome-linked ).
3. Disorder of globin synthesis.
   1. Thalassemia.
   2. Hemoglobinopathies.