Mean Corpuscular Volume (MCV) Calculator

Variables and formula

The mean corpuscular volume (MCV) is one of the three Red Blood Cell (RBC) indices and considered to be the most important because of the involvement in anemia diagnosis and determination of Red Blood Cell Distribution Width (RDW).

The other two indices are Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC).

This erythrocyte parameter can be measured through automated hematology analysis or estimated via the following equation:

MCV in fL = (Hematocrit %) / (RBC x 10¹²/L) x 10

The measurement unit is the femtoliter, which is equivalent to 10^-15 L.

The normal values for hematocrit, RBC and MCV can be found in the table below:

* Please note that this interval is that given by the American Association for Clinical Chemistry. Other sources indicate MCV normal range as: 80 – 100 fL or 83 – 97 fL.

MCV measurement through automated hematology analysis is done after blood is drawn, usually from one of the veins of the arms.

Some patients may experience moderate pain or discomfort and a sensation of prick but there are no major health risks associated with this procedure.

Increased MCV

MCV values that are higher than normal mean that erythrocytes are enlarged. This is suggestive of Macrocytic or pernicious anemia.

MCV can reach as high as 150 fL, when normal high values are up to 100 fL. Macrocytic anemia is most likely caused by:

■ B12 deficiency;

■ Folate deficiency;

■ Chemotherapy.

When high MCV is associated with an elevated GGT and an AST to ALT ratio of 2:1, alcoholism diagnosis is likely.

Erythrocytes may be abnormally swollen in severe hyperglycemia or in the presence of RBC agglutination (in paraproteinemia), thus leading to a false elevation of MCV.

Decreased MCV

When MCV values are lower than normal (going as low as 60 fL, when normal low is around 80 fL), the red blood cells are likely to be smaller than average. This finding is suggestive of microcytic anemia, a condition that is caused by the following:

■ Iron deficiency (inadequate diet intake);

■ Gastrointestinal blood loss;

■ Thalassemia;

■ Chronic diseases.

Normocytic anemia

This is a condition in which the size of the RBCs may be within norms but other indices, such as MCH or MCHC may be abnormal. The main causes of normocytic anemia include:

■ Sudden blood loss (when the bone marrow hasn’t yet responded to the change in volume);

■ Hemolysis;

■ Presence of sepsis;

■ Malignancy;

■ Kidney failure;

■ Presence of prosthetic heart valves.

References

1. Williams WJ. Examination of the blood. In: Williams WJ, Beutler E, Erslev AJ, Lichtman MA, eds. Hematology, 3d ed. New York: McGraw-Hill, 1983;9–14.

2. The McGill Physiology Virtual Lab (2016) Blood cell indices > MCV and MCHC.

3. Bessman JD, Gilmer PR Jr, Gardner FH. Improved classification of anemias by MCV and RDW. Am J Clin Pathol. 1983; 80(3):322-6.