II. Indication
- Detecting HIV related Immune Deficiency (most accurate measure)
- Monitoring HIV Disease
- Used in combination with Plasma Viral Load Testing
III. Efficacy
- Advantages
- Best marker of of Immune SystemImpairment
- Roughly correlated to duration and activity of HIV Infection
- Best predicts prognosis
- CD4 Cell Counts have variability
- Vary from person to person even given the same HIV severity
- Vary widely from lab to lab
- Use the same lab to follow patients
- Diurnal CD4 Cell Count variation (from 50-150 cells/mcl)
- CD4 Count may drop 50% with acute comorbid illness (e.g. Influenza, Pyelonephritis)
IV. Normal
- Non-HIV patients: 800-1200 cells/mcl
V. Interpretation
- See HIV Course
- Each CD4 Count 10% rise decreases progression risk 15%
- Stage 1: CD4 500 Cells/mm3 or more
- Stage 2: CD4 200 to 499 Cells/mm3
- Stage 3: CD4 <200 Cells/mm3 or AIDS-Defining Illness