Final answer:
Spherocytes are associated with increased osmotic fragility due to their spherical shape which lacks the central pallor of normal red blood cells. This makes them more prone to hemolysis.
Step-by-step explanation:
Spherocytes are characteristic of certain types of hemolytic anemia and are associated with increased osmotic fragility. Unlike normal red blood cells that have a central pallor, spherocytes lack this central pallor due to their spherical shape. Their altered shape makes them more prone to rupture when placed in hypotonic solutions, which is a measure of osmotic fragility. Sickle cells, on the other hand, are characteristic of sickle cell anemia, a disorder caused by abnormal hemoglobin that results in red blood cells assuming a sickle shape at low oxygen concentrations. Both of these abnormal red blood cell shapes can lead to various complications, including an increased rate of hemolysis and anemia.