MCHC is increased in

Ref Robbins 9/e p633 MCHC can be elevated ("polychromatic") in hereditary spherocytosis, sickle cell disease and homozygous haemoglobin C disease, depending upon the hemocytometer. MCHCcan be elevated in some megaloblastic anemias. Spherocytosis most often refers to hereditary spherocytosis. This is caused by a molecular defect in one or more of the proteins of the red blood cell cytoskeleton, including spectrin, ankyrin, Band 3, or Protein 4.2. Because the cell skeleton has a defect, the blood cell contracts to a sphere, which is its most surface tension efficient and least flexible configuration. Though the spherocytes have a smaller surface area through which oxygen and carbon dioxide can be exchanged, they in themselves perform adequately to maintain healthy oxygen supplies. However, they have a high osmotic fragility--when placed into water, they are more likely to burst than normal red blood cells. These cells are more prone to physical degradation.