What it is: A CD4+ T-cell count measures the number of CD4 cells (a type of white blood cell also called helper T-cells) in a blood sample, using flow cytometry.
Why it's ordered: Most often ordered to stage HIV infection and monitor how well antiretroviral therapy is working; occasionally used to assess immune status in other conditions.
What it detects: CD4 cells help coordinate the immune system's response to infection. HIV specifically destroys CD4 cells, so a declining count signals worsening immune impairment, while a rising count on treatment signals immune recovery.
Collection & prep: A standard blood draw from a vein in the arm. No special preparation is required.
Results:
Normal – generally above 500 cells/µL
Low – indicates a weakened immune system; counts below 200 cells/µL define AIDS in someone with HIV
Possible complications of a low CD4 count: A significantly reduced CD4 count raises the risk of opportunistic infections, so results are used alongside viral load testing to guide treatment decisions and monitor a person's immune health over time.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
