Test measures presence of spherocytes and spheroidal cells. Test is not specific for hereditary spherocytosis. A large amount of blood and trauma free venipuncture are needed. It is associated with a compensated or uncompensated hemolytic state which is relieved by splenectomy. Serum aldolase activity may be decreased in some cases of heredity spherocytosis.
Osmotic fragility is increased in cases of malaria infestation.