Leukocytosis

Definition

Leukocytosis is an elevation of the white blood cell (WBC) count above the normal range (typically >11,000/µL in adults). It usually indicates infection, inflammation, or hematologic disorder.

Causes

• Bacterial infection (most common)
• Inflammation (trauma, surgery, burns)
• Stress (physical or emotional)
• Medications (corticosteroids, lithium)
• Leukemia
• Dehydration

Differential Significance

• Neutrophilia: bacterial infection, stress
• Lymphocytosis: viral infection, pertussis
• Eosinophilia: allergy, parasitic infection
• Basophilia: CML, allergic reaction
• 'Left shift' (increased bands): acute bacterial infection

Nursing Interventions

Assess for source of infection, monitor temperature, administer antibiotics as ordered (cultures before antibiotics when possible). Identify underlying cause; treat inflammation or manage malignancy.

NCLEX Relevance

Left shift (elevated bands) = acute bacterial infection.