Clinical smaller RBCs, having diameter less than 6

Clinical Significance

Abnormal morphology of RBC must be reported along with peripheral blood smear. This is helpful in the diagnosis of various types of anaemia and other diseases like malaria, thalassemia, etc.

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Following types of abnormalities are seen with RBC.

Colour Reaction

Hypochromic RBC:

Hypochromic RBCs have increased central paler area. It is associated with iron deficiency that decrease Hb conc. Presence of hypochromic RBCs is called as hypochromatism.

Hyperchromic RBC:

Hyperchromic RBCs have decreased central pale area. It is associated with increased iron conc. and Hb. conc. These RBC shows extensive staining than normal RBC. The presence of hyperchromic RBC is known as hyperchromatism.

Anisochromic RBC:

Anisochromic RBC have variable intensities, i.e. it has unequal Hb conc. These RBCs are seen in iron deficiency anaemia. Presence of such RBC is known as anisochromatism.

Polychromic RBC:

Polychromic RBCs are gray coloured. It may be slightly larger in size. It is often associated with increased reticulocyte count. Presence of polychromic RBC is known as polychromatism.

Size Variations

Microcytic RBC:

Microcytic RBCs are smaller RBCs, having diameter less than 6 ?. These are present in thalassemia, iron deficiency anemia, or it may be hereditary. Presence of microcytic RBC is known as microcytosis.

Macrocytic RBC:

The macrocytic RBCs are larger RBCs, having diameter 7.8 ?. It is associated with megaloblastic anaemia. The presence of macrocytic RBC is known as macrocytosis.

Anisocytic RBC:

Anisocytic RBCs are variable in their size. It can be seen in various types of leukemia and iron deficiency anaemia. Presence of anisocytic RBC is known as anisocytosis.

Shape Variation


Poikilocytic RBCs have variation in their shape. It may be dumb-bell like or slightly curved, etc. Defective bone marrow production causes poikilocytosis.


These RBCs have stomata like shape, i.e. central paler area is elongated silt like. This is often associated with alcoholism, hepatic disease or it may be hereditary.


These RBCs are elliptical, cigar shaped. Low count of elliptical RBC may be considered as normal. It is associated with various anaemia; thalassemia or .it may be hereditary eliptocytosis.


These are spherical RBC without any central paler area. These are usually slightly smaller in size. Spherocytes can be seen in haemolytic anaemia, renal diseases. The presence of spherocyte is known as spherocytosis.

Sickle Cells:

These are half moon shaped cells, which often have pointed ends. Normal RBC tends to be sickle shaped due to abnormal Hb. The disease is also known as sickle cell anaemia.

Target Cells:

These are also known as liptocytes and their presence is known as liptocytosis. The shape of target cell is bell like or hood like. These have central staired area. Such RBCs are found in hepatitis, thalassemia, etc.


These RBCs are oval in shape. The lower count of ovalocytes may be considered to be normal. However, the higher count is associated with various anaemias.


These RBCs are irregular shaped, with throne like projections on their outer edges. Their presence is called as acanthocytosis. Such types of RBCs can be seen in hepatic and renal disorder.

Abnormalities in Normal Content of RBC:

Nucleated RBC:

These are immature RBCs with nucleus. These are also called as erythroblast. These are seen in megaloblastic anaemia, severe bleeding, and leukemia.

Heinz Bodies:

These are mature cells with deposit of iron which stains dark blue.

Howell-Jolly Body:

In these RBC contains round purple stained nuclear fragment. Normally, these are present in immature RBCs. These can be seen in RBCs with various types of anaemia.