Diagnostic Tests Associated with the Immune System

White Blood Cells (WBC)

• Normal Range: 5,000 - 10,000
• Leukocytosis: WBC > 10,000, indicating infection.
• Leukopenia: WBC < 4,000, indicating:
  • Cancer
  • Autoimmune disorders
  • Medication effects
  • Infections
• Risk with Leukopenia: Increased risk of infection due to insufficient WBCs.

Neutrophils

• Normal Range: 2,500 - 8,000
• Neutropenia: Neutrophils < 2,000
• Left Shift/Banded Neutrophils:
  • Occurs when bone marrow releases immature neutrophils during overwhelming infections.
  • Indicates the body is struggling to keep up with infection demand.

ESR (Erythrocyte Sedimentation Rate)

• Normal Level: < 20
• Elevated ESR: > 20 indicates inflammation.

CRP (C-reactive Protein)

• Normal Level: < 3
• Elevated CRP: > 3 indicates inflammation.
• Memory Aid: CRP has three letters, normal is under three.

Differential White Blood Cell Count

• Purpose: Helps determine the type of infection or disorder (e.g., cancer, autoimmune disorder).
• Types of White Blood Cells:
  • Neutrophils: 55% - 75%
    • Elevated during acute bacterial infections.
    • "First to neutralize the threat."
  • Lymphocytes: 20% - 40%
    • Elevated during bacterial, viral infections, leukemia, and lymphoma.
  • Monocytes: 2% - 8%
    • Elevated with bacterial infections and tuberculosis.
  • Eosinophils: 1% - 4%
    • Elevated during allergic reactions and parasitic infections.
  • Basophils: 0.5% - 1%
    • Elevated during allergic reactions.
    • Release histamine, often requiring antihistamines like Benadryl.
    • Memory Aid: "Basophils - think allergic reaction and Benadryl."

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• Discussion on disorders starting with lupus in the next video.