Hematology Basics- MCV & RDW
The mean corpuscular volume (MCV) is the volume of the "average" red blood cell (RBC) stated in femtoliters (fL). The normal range of the MCV in adults is 80 to 96 fL. Normal values in newborns, children, and adolescents are dependent upon age.
●Macrocytosis – Macrocytosis is present when the MCV is >100 fL; Values >115 fL are almost exclusively seen in vitamin B12 or folate deficiency, or following the use of hydroxyurea. Other causes include MDS, Aplastic anaemia, Alcohol etc
●Microcytosis – Microcytosis is present when the MCV is <80 fl. The three most common causes in clinical practice are iron deficiency, the anemia of (chronic) inflammation, and thalassemia trait.
●Red cell distribution width – The red cell distribution width (RDW) is a measure of the dispersion of values of the volume of individual red cells about the MCV; its normal range is from 11.5 to 14.5 percent. An increased RDW indicates the presence of increased variability in red cell size (ie, anisocytosis).
•The finding of an increased RDW is not specific for any one hematologic abnormality
eg, macrocytes-megaloblastic -Increased MCV & RDW , microcytes- Iron deficiency- Decreased MCV & Increased RDW, or reticulocytes-hemolysis-.Increased MCV & RDW).
