What are the indications of a false positive acidified serum lysis and Ham test for paroxysmal nocturnal hemoglobinuria (PNH)?

Updated: May 20, 2021
  • Author: Emmanuel C Besa, MD; Chief Editor: Sara J Grethlein, MD, FACP  more...
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A false-positive test result is seen in congenital dyserythropoietic anemia, type II (hereditary erythroblastic multinuclearity with positive acidified serum tests [HEMPAS]). These patients have a negative sucrose hemolysis ("sugar water test") result. Some normal serum can give a false-negative Ham test result; thus, the sucrose water test is more sensitive but less specific for paroxysmal nocturnal hemoglobinuria (PNH).

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