How is the severity of hereditary spherocytosis (HS) graded?

• Mild HS
  • Normal Hb level with reticulocytes < 6%.
  • May require 0-1 transfusion during lifetime and rarely splenectomy.
• Moderate HS
  • Hb level > 8 g/dL (80 g/L) with reticulocytes 6%-10%.
  • May require 0-2 transfusions during infancy and in some cases splenectomy (if the capacity level is decreased).
• Moderately severe HS
  • Hb level 6-8 g/dL (60-80 g/L) with reticulocytes > 10%.
  • May require > 2 transfusions intermittently and splenectomy likely necessary.
• Severe HS
  • Hb level 10%.
  • Require regular transfusions and splenectomy likely necessary.

2012 British Committee Standards in Haematology (BCSH) expert guideline on diagnosis of hereditary spherocytosis:

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