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Haemolytic Screen
Haemolytic Screen

Blood Film

January 20th, 2018


Abnormally shaped red blood cells.
  • Significance

  • Certain red cell morphologies may be more suggestive of certain causes of haemolysis.
  • Poikilocytosis
  • Interpretation

  • Schistocytes: small irregular fragments of red blood cells of varying shapesMicroangiopathic haemolytic anaemia, mechanical haemolysis, thalassaemia
  • Sickle cells (drepanocytes): crescent-shaped cells caused by aggregation of haemoglobin SSickle cell disease
  • Spherocytes: round cells with loss of central pallor, due to removal of a portion of the cell membrane by phagocytesHereditary spherocytosis, immune haemolysis, Clostridium
  • Microspherocytes: small round cells with loss of central pallor (essentially spherocytic schistocytes)Hereditary spherocytosis, microangiopathic haemolysis, burns
  • Irregularly contracted cells: loss of central pallor with an irregular borderOxidative haemolysis - G6PD deficiency, unstable haemoglobins, drugs
  • Prekeratocytes (blister cells)  - central holeOxidative haemolysis - G6PD deficiency, unstable haemoglobins, drugs
  • Keratocytes (bite cells): bite-like defect in the membrane of the cell, due to phagocytosis of a Heinz bodyOxidative haemolysis - G6PD deficiency, unstable haemoglobins, drugs

Inclusion Bodies

Stainable material within red blood cells, mainly due to retained remnants of cellular components.
  • Inclusion Bodies
  • Interpretation

  • Nucleated red blood cellsSevere anaemia, severe sepsis, hypoxia, myelofibrosis, bone marrow infiltration
  • Heinz bodies (denatured haemoglobin): basophilic inclusions adjacent to the cell membrane on supravital stainingOxidative haemolysis - G6PD deficiency, unstable haemoglobins, drugs


Red cells with a bluish tinge due to persistence of ribosomes.
  • Polychromasia
  • Significance

  • Indicative of reticulocytosis.
  • Causes of Polychromasia

  • Haemolytic anaemia
  • Haemorrhage (acute or chronic)
  • Recovery post bone marrow suppression
  • Late pregnancy
  • High altitude
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