This antibody labels the CD45 protein on the membrane of the leucocytes including lymphocytes, macrophages, and granulocytes in both normal and neoplastic tissue. CD45 is detected in a large majority of hemotopoietic-lymphoid neoplasms, i.e. leukemia and malignant lymphomas. Certain types of lymphoid neoplasms may lack CD45 cxpression (i.e. Hodgkin's disease, some T-cell lymphomas, and some leukemia). It may be useful when used in a panel of antibodies.