Increased osmotic fragility seen in

Ans. is 'd' i.e., Hereditary spherocytosisOsmotic fragility of Red blood cells.Red blood cell osmotic fragility is the resistance of RBC hemolysis to osmotic changes.Normally RBC maintains osmotic equilibrium with the surrounding medium i.e., with serum that has 0.9% NaCI.As the surrounding medium becomes hypotonic fluid will enter into the cell along osmotic gradiant, eventuallyunder very hypotonic conditions the cell will enlarge to capacity and rupture Osmotic lysis.Osmotic fragility is determined by measuring the degree of hemolysis in hypotonic saline. Normal red cell begins to lyse at 0.5% NaC1 and the hemolysis is complete at 0.3 NaCl.Red blood cells osmotic fragility is considered to be increased if hemolysis occur in a NaCI concentration > 0-5%.Osmotic fragility is considered to be decreased if the hemolysis is not complete in a 0-3% of NaCI.