Clinical utility of RBC indices in anemia investigations
Anemia can be caused by a range of conditions, and symptoms are often non-specific. To help identify the underlying cause, anemias are classified according to the size of the red cells, as being normocytic (normal mean cell volume), macrocytic (increased mean cell volume), or microcytic (decreased mean cell volume).

Laboratory testing therefore begins with a complete blood count. Red blood cell indices such as the mean cell volume (MCV) and the distribution width (RDW) of the cells are especially useful, as these parameters often become abnormal before anemia becomes noticeable in other routine testing.
Read more about the utility of the RBC indices of a CBC in Anemia investigations