Ham test

Ham Test

A test that assesses susceptibility of erythrocytes to hemolysis, which is markedly increased in paroxysmal nocturnal hemoglobinuria (PNH); see there.
Principle In acidified serum, complement is activated by the alternate pathway, binds to RBCs, and lyses PNH cells which are sensitive to complement activation; positive Ham test also occurs in the rare congenital dyserythropoietic anemia type II, also known as HEMPAS

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hemoglobinuria [he″mo-glo″bĭ-nu´re-ah]

the presence of free hemoglobin in the urine. adj., adj hemoglobinu´ric.

march hemoglobinuria hemolysis caused by repeated uncushioned shocks or trauma to some body part, such as in some soldiers on long marches, in marathon runners, and in karate practitioners.

paroxysmal cold hemoglobinuria an autoimmune or postviral disease in which there is a biphasic IgG antibody directed against the P blood group antigen. It is marked by episodes of hemoglobinemia and hemoglobinuria after exposure to cold and is detected by the Donath-Landsteiner test. The condition is treated with prednisone and cyclophosphamide and by protection from exposure to cold.

paroxysmal nocturnal hemoglobinuria (PNH) an acquired blood cell abnormality with proliferation of abnormal red blood cells (PNH cells) that are readily hemolyzed by complement, and episodes of severe hemolysis and thrombosis, particularly of the hepatic veins. It is detected by the ham test. Treatment is with androgens or prednisone and, during thrombotic episodes, with heparin.