Measurement of the number of lymphocytes expressing the CD4 antigen on their surface in a specified volume of whole blood. CD4 is a membrane glycoprotein found primarily on T lymphocytes, but also can be expressed on B cells, macrophages, and granulocytes. On T cells it is a co-receptor for the T cell receptor (TCR), interacts with MHC class II antigens, and functions to initiate or augment the early phase of T-cell activation.
blood CD8 cell count +
blood natural killer T cell count
blood R73 cell count +
blood regulatory T cell count +
blood RT6.1 cell count +
blood RT6.2 cell count
blood T lymphocyte count to total leukocyte count ratio
blood T lymphocyte count to total lymphocyte count ratio +