A site for medical students - Practical,Theory,Osce Notes

Clinical significance of Osmotic Fragility

Osmotic fragility of red cells is defined as the ease with which red cells are ruptured (hemolysed) when they are exposed to hypotonic solution.
Osmotic fragility test assesses the integrity of the membrane of red cells.

Increased Osmotic Fragility is seen in the following
Cells which have a lower surface to volume ratio such as spherocytes from any cause have increased osmotic fragility is ssen in the following Conditions
  • Hereditary»spherocytosis (HS)
  • Autoimmune Hemolytic Anemias (A1HA)
  • Hemolytic Disease of new bom
  • Malaria
  • Severe pyruvate kinase deficiency
  • Other conditions in which spherocytes are found in the blood 

Conditions with decreased Osmotic Fragility
Cells which have a high surface to volume ratio such as thin/hypochromic/target cells have decreased osmotic fragility.
  • Thalassemia
  • Other hemoglobinopathies eg. HbC, HbS
  • Iron deficiency anemia
  • Sickle cel! anemia
  • Post splenectomy
  • Reticulocytosis
  • Other conditions in which thin/target cells are found in the blood.