Test Details: Sudan Black B has been used to stain phospholipids and intracellular lipids. Staining pattern is almost similar to myeloperoxidase reaction, with positive staining of granulocytic cells, eosinophils and weak monocytic staining. It doesn′t stain lymphocytes. Sudan Black B can be used to stain older blood or bone marrow smears, but the stain slightly fades over time. Sudan Black B stains phospholipids grey and neutral fats blue-black. This test is useful for the differentiation of Acute myeloid leukaemia (AML) from Acute lymphoid leukaemia (ALL).