We studied 81 cases of ALL using immunoperoxidase stain for nuclear terminal deoxynucleotidyl transferase (TdT) and immunoalkaline phosphatase stain for surface markers (using monoclonal antibody J5 for common ALL antigen [CALLA], Leu-1 for pan-T antigen, and B1 for pan-B antigen) on air-dried smears.