Immunophenotyping detects the presence or absence of white blood cell (WBC) antigens. These antigens are protein structures found on the surface or interior of WBCs. Typical groupings of antigens are present on normal WBCs and are unique to specific cell types. Atypical but characteristic groupings are seen with leukemias and lymphomas. This allows immunophenotyping to be useful in helping to diagnose and classify these blood cell cancers.