CD4 Cell Count details

CD4 cells (also called 'helper T-cells') are a key type of white blood cell that coordinates much of your immune system's response to infection. This test counts how many CD4 cells are circulating in your blood, and it's most widely used to monitor immune health in people with HIV, since the virus specifically infects and depletes CD4 cells over time — a declining count signals weakening immunity and increasing risk of opportunistic infections, while a rising count on antiretroviral treatment reflects immune recovery. CD4 counts also guide decisions about starting preventive medications against certain infections at specific thresholds, and can be used, less commonly, to evaluate other conditions affecting immune function.