Lymphocyte Differentiation Marker - Lymphocyte CD5 Surface Marker Test

Flow cytometry is used to determine the expression of CD5 protein on the surface of lymphocytes. CD5 is normally expressed on most T lymphocytes and a small proportion of B cells (B-1a). Differentiation in its expression pattern is an important diagnostic tool for distinguishing between B and T lymphomas, particularly chronic lymphocytic leukemia (CLL), where cancerous B cells express CD5.