Dehydrated hereditary stomatocytosis (DHS) is a rare hemolytic anemia characterized by a decreased red cell osmotic fragility due to a defect in cation permeability, resulting in red cell dehydration and mild to moderate compensated hemolysis. Pseudohyperkalemia (loss of potassium ions from red cells on storage at room temperature) is sometimes observed. The disease is Monarch Disease Ontology id MONDO_0017910 (dehydrated hereditary stomatocytosis). Also known as: hereditary xerocytosis.