Blood Test Guide

CD4 Count (T-Cell Count)

CD4 count measures the immune cells HIV attacks. It tracks HIV disease progression and when to start treatment to protect against opportunistic infections.

CD4 count reference ranges

CD4 CountInterpretation
500–1,500 cells/µLNormal immune system
350–499 cells/µLMildly reduced — treatment recommended
200–349 cells/µLSignificantly reduced — high infection risk
<200 cells/µLAIDS diagnosis — very high risk of opportunistic infections
<50 cells/µLSevere AIDS — risk of CMV retinitis, MAC, cryptococcal meningitis

CD4 count and HIV treatment

When to start antiretroviral therapy (ART)

Current guidelines recommend starting ART for ALL people with HIV regardless of CD4 count — the earlier, the better. CD4 count is used to monitor immune recovery on treatment. With effective ART, CD4 counts typically rise by 50–150 cells/µL per year. The goal is to achieve a CD4 count above 500 cells/µL. People with CD4 <200 also need prophylaxis against Pneumocystis pneumonia (PCP) with trimethoprim-sulfamethoxazole.

CD4 count vs HIV viral load

TestWhat it measuresClinical use
CD4 countImmune system strengthMonitors immune recovery, predicts infection risk
HIV viral loadAmount of HIV in bloodMonitors treatment effectiveness — goal is undetectable

Questions to ask your HIV doctor

Medical Disclaimer: For educational purposes only. Always consult a qualified healthcare professional for diagnosis and treatment.