Division of Haematological Pathology

Haematological Atlas  - Red blood cell morphology

 

Red Cell Morphological Abnormalities

Hypochromasia

Morphology:
Increase in the red cells' central pallor which occupies more than the normal third of the red cell diameter.

Found in:
Iron deficiency
Thalassaemia
And any of the conditions leading to microcytosis

 

Polychromasia

Morphology:
Red cells stain shades of blue-gray as a consequence of uptake of both eosin (by haemoglobin) and basic dyes (by residual ribosomal RNA). Often slightly larger than normal red cells and round in shape - round macrocytosis.

Found in:
Any situation with reticulocytosis - for example bleeding, haemolysis or response to haematinic factor replacement.

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Anisocytosis

Morphology:
An increase in the variability of red cell size.Variation in erythrocyte size is now measured by the red cell distribution width (RDW). Always take the RDW into acount when interpreting the mean corpuscular volume (MCV).

 

Microcytosis

Morphology:
Decrease in the red cell size. Red cells are smaller than ± 7µm in diameter. The nucleus of a small lymphocyte (± 8,µm) is a useful guide to the size of a red cell.

Found in:
Iron deficiency anaemia
Thalassaemia
Sideroblastic anaemia
Lead poisoning
Anaemia of chronic disease

 

Macrocytosis

Morphology:
Increase in the size of a red cell. Red cells are larger than 9µm in diameter. May be round or oval in shape, the diagnostic significance being different.

Found in:
Folate and B12 deficiencies (oval)
Ethanol (round)
Liver disease (round)
Reticulocytosis (round)

 

 

Dimorphic Blood Picture

Morphology:
Two distinct populations of red cells.The populations may differ in size, shape or haemoglobin content.

Found in:
Anaemic patient after transfusion
Iron deficiency patient's taking supplements
Combined B12 / folate and iron deficiency
Sideroblastic anaemia

 

Spherocytosis


Morphology:
Red cells are more spherical. Lack the central area of pallor on a stained blood film.

Found in:
Hereditary spherocytosis
Immune haemolytic anaemia
Zieve's syndrome
Microangiopathic haemolytic anaemia.

 

Stomatocytosis

Morphology:
Red cells with a central linear slit or stoma. Seen as mouth-shaped form in peripheral smear.

Found in:
Alcohol excess
Alcoholic liver disease
Hereditary stomatocytosis
Hereditary spherocytosis

 

Acanthocytosis

Morphology:
Spherical cells with 2 - 20 spicules of unequal length and distributed unevenly over the red cell surface.

Found in:
Liver disease
Post splenectomy
Anorexia nervosa and starvation

 

Target Cells

Morphology:
Red cells have an area of increased staining which appears in the area of central pallor.

Found in:
Obstructive liver disease
Severe iron deficiency
Thalassaemia
Haemoglobinopathies (S and C)
Post splenectomy

 

Elliptocytosis

Morphology:
The red cells are oval or elliptical in shape. Long axis is twice the short axis.

Found in:
Hereditary elliptocytosis
Megaloblastic anaemia
Iron deficiency
Thalassaemia
Myelofibrosis

 

Cigar Cells

Morphology:
Red cells shaped like a cigar or pencil

Found in:
Iron deficiency

 

Schistocytosis

Morphology:
Fragmentation of the red cells.

Found in:
DIC
Micro angiopathic haemolytic anaemia
Mechanical haemolytic anaemaia

 

Echinocytes

Morphology:
Red cells are covered with 10 - 30 short spicules of regular form.

Found in:
Uraemia
Severe burns
EDTA artefact
Liver disease

 

Sickle Cells

Morphology:
Sickle shaped red cells

Found in:
Hb-S disease

 

Tear Drop Cells

Morphology:
Red cells shaped like a tear drop or pear

Found in:
Bone marrow fibrosis
Megaloblastic anaemia
Iron deficiency
Thalassaemia

 

Rouleaux Formation

Morphology:
Stacks of RBC's resembling a stack of coins

Found in:
Hyperfibrinogenaemia
Hyperglobulinaemia

 

Red cell-agglutination

Morphology:
Irregular clumps of red cells

Found in:
Cold agglutinins
Warm auto immune haemolysis

 

Howell-Jolly Bodies

Morphology:
Small round cytoplasmic red cell inclusion with same staining characteristics as nucleus.

Found in:
Haemolytic anaemias
Post splenectomy
Megaloblastic anaemia

 

Malaria Parasities

Plasmodium falciparum

Morphology:
Ring form of Pl falciparum in red cells. Delicate rings with 1 or 2 chromatin dots. Often more than one ring in a red cell. Accolé forms are found.

Found in:
Malaria

 

Basophilic stippling

Morphology:
Considerable numbers of small basophilic inclusions in red cells.

Found in:
Thalassaemia
Megaloblastic anaemia
Haemolytic anaemia
Liver disease
Heavy metal poisoning