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. Labs: Normal
- Non-HIV patients: 800-1200 cells/mcl
V. Labs: 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
VI. Labs: Surrogates for CD4 Count
- Patient medical records and CD4 Count may be unavailable to emergency providers
- Surrogates for low CD4 Counts <200 Cells/mm3
- Absolute Lymphocyte Count (ALC) <1000 to 1250 cells/mm3
- Prophylactic Antibiotic daily use found on medication reconciliation
- Trimethoprim-Sulfamethoxazole
- Dapsone
- Pentamidine
- Azithromycin
- Fluconazole
VII. References
- Parker and Bond (2023) Crit Dec Emerg Med 37(10): 4-9
- GoldSchmidt (2016) Am Fam Physician 94(9): 708-16 [PubMed]
- Hughes (1997) Ann Intern Med 126:929-38 [PubMed]
- Mellors (1997) Ann Intern Med 126:946-54 [PubMed]
- O'Brien (1997) Ann Intern Med 126:939-45 [PubMed]