Patients should be selected for splenectomy on the basis of their clinical symptoms and presence of complications such as gallstones, not simply on the basis of the diagnosis alone (grade 2 recommendation, grade C evidence). Splenectomy should be performed in children with severe HS, considered in those who have moderate disease, and should probably not be performed in those with mild disease. A careful history is important in those with moderate to mild disease to establish if there is evidence suggesting reduced exercise tolerance; the metabolic burden of increased marrow turnover may be considerable. Where there is a family history, the benefit of splenectomy in other individuals may help determine whether to proceed.