THE MERCK MANUAL: The Merck Manual of Diagnosis and Therapymultimedia


  • Overview of Hemolytic Anemia
  • Hereditary Spherocytosis and Hereditary Elliptocytosis
  • Spherocytes in Hemolytic Anemia

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    Spherocytes in Hemolytic Anemia

    The presence of spherocytes in the peripheral blood smear suggests either hereditary spherocytosis (HS) or autoimmune hemolytic anemia (AIHA). Spherocytes have increased osmotic fragility (because of decreased distensibility associated with reduced surface membrane area) in hypotonic saline, and this test (osmotic fragility test) is positive in HS and in AIHA. The antiglobulin (Coombs) test distinguishes between them; the result is positive in AIHA and negative in HS.

    By permission of the publisher. From Tefferi A, Li C. In Atlas of Clinical Hematology. Edited by JO Armitage. Philadelphia, Current Medicine, 2004.