The mean corpuscular volume, or "mean cell volume" (MCV), is a measure of the average red blood cell size that is reported as part of a standard complete blood count. The MCV is calculated by dividing the total volume 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 centrifuge.
In patients with anemia, it is the MCV measurement that allows classification as either a microcytic anemia (MCV below normal range), normocytic anemia (MCV within normal range) or macrocytic anemia (MCV above normal range).
- To calculate the MCV, expressed in femtoliters (fL, or 10-15L), the following formula is used:10 x hematocrit (%) divided by RBC count (millions/μL). The normal range for MCV is: 80-99 fL.
- Use of volume-sensitive automated blood cell counters, such as the Coulter counter. In this type of apparatus, the red cells pass one-by-one through a small aperture and generate a signal directly proportional to their volume.
- Other automated counters measure red blood cell volume by means of techniques that measure refracted, diffracted, or scattered light.
If the MCV was determined by automated equipment, the result can be compared to RBC morphology on a peripheral blood smear. Any deviation would be indicative of either faulty equipment or technician error.
For further specification, it can be used to calculate red blood cell distribution width
Read more about Mean Corpuscular Volume: Worked Example
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