CD4 cells are a type of white blood cell (lymphocyte) that play a key role in the immune system.

HIV targets and destroys CD4 cells, leading to immune suppression.

The CD4 count helps determine:

Stage of HIV infection.

Risk of opportunistic infections.

Effectiveness of antiretroviral therapy (ART).

Clinical uses include:

Monitoring immune status in HIV patients.

Assessing response to ART.

Guiding prophylaxis for opportunistic infections (e.g., Pneumocystis pneumonia).

Often performed alongside HIV viral load testing for comprehensive management.

Analyte: CD4+ T‑lymphocyte count in blood.

Normal Range (varies by lab): ~500–1,500 cells/µL.

Abnormal Findings:

Low CD4 count (<200 cells/µL): Severe immunosuppression, high risk of opportunistic infections.

Moderately low CD4 count (200–500 cells/µL): Increased risk of infections, indicates progression of HIV.

Clinical Use:

Provides a direct measure of immune system strength.

Helps guide HIV treatment and infection prevention strategies.

Supports infectious disease, immunology, and internal medicine evaluations.