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Haemolytic Screen
Haemolytic Screen

Blood Film



  • 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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