This document discusses various laboratory methods for evaluating cellular immunity, including leukocyte phenotyping using flow cytometry to identify cell surface markers, delayed type hypersensitivity skin testing to assess memory T cell responses, lymphocyte activation assays to measure proliferation and cytokine production following stimulation, and assays of monocyte and neutrophil function like chemotaxis and phagocytosis. Flow cytometry is highlighted as the most widely used method for immunophenotyping and allows rapid identification and quantification of leukocyte subsets.