Reduction of total circulating red cell mass below normal limits.

OR

Decrease in the oxygen carrying capacity of the blood that leads to tissue hypoxia.

Anemia may be absolute (decreased RBC mass), or relative ( associated with higher plasma volume).

Classification of anemia

1. Morphological classification

• Red red cell size ( normocytic, microcytic, or macrocytic)
• Degree degree of hemoglobinization( normochromic or hypochromic)

2. Etiological classification – given below in the tables

Morphological classification of anemia.

Etiological classification of anemia

Source – textbook of pathology ( Ramdas Nayak )