What does a leukocytosis (white blood cell count) of 14.4 indicate in a female in her 50s?

Leukocytosis of 14.4 in a Female in Her 50s

A white blood cell count of 14.4 × 10⁹/L in a woman in her 50s most commonly indicates an active bacterial infection and warrants immediate clinical evaluation for infection sources, though physiological stress, medications (particularly corticosteroids or lithium), smoking, obesity, and chronic inflammatory conditions must also be considered. 1

Primary Diagnostic Consideration: Bacterial Infection

Bacterial infection is the leading cause of leukocytosis and should be your first consideration. 1 A WBC of 14.4 meets the threshold (≥14,000 cells/mm³) that carries a likelihood ratio of 3.7 for documented bacterial infection. 2

Key Diagnostic Steps for Infection

Obtain a complete blood count with manual differential immediately to assess the following critical markers (in order of diagnostic power): 1, 2

• Absolute band neutrophil count ≥1,500 cells/mm³ (likelihood ratio 14.5 for bacterial infection) 1, 2
• Neutrophil percentage >90% (likelihood ratio 7.5) 1, 2
• Left shift ≥16% band neutrophils (likelihood ratio 4.7, even with normal total WBC) 1, 2

Common Bacterial Sources to Evaluate

Systematically assess for: 1, 2

• Respiratory tract infections (consider chest imaging if respiratory symptoms present) 3
• Urinary tract infections (obtain urinalysis with culture for urinary symptoms) 2
• Skin and soft tissue infections 1
• Gastrointestinal infections (evaluate for abdominal pain, diarrhea, peritoneal signs) 2
• Spontaneous bacterial peritonitis if patient has cirrhosis with ascites 1

Clinical Assessment for Infection

Look specifically for: 1, 3

• Fever or signs of sepsis
• Localizing symptoms pointing to infection source
• Blood cultures if systemic infection suspected 2
• Site-specific cultures as indicated 2

Secondary Causes to Consider

Physiological and Stress-Related

Physical or emotional stress can cause leukocytosis through catecholamine and cortisol release, mobilizing neutrophils from bone marrow storage pools. 1, 3 The WBC can double within hours after surgery, exercise, trauma, or emotional stress. 4, 5

Medication-Induced Leukocytosis

Review current medications carefully: 1, 3

• Corticosteroids (most common medication cause) 1
• Lithium (consistently causes leukocytosis; WBC <4,000/mm³ would be unusual in lithium-treated patients) 1, 3
• Beta-agonists and epinephrine 1, 2

Chronic Non-Infectious Causes

Consider baseline factors: 1

• Smoking (associated with higher baseline WBC)
• Obesity (associated with elevated WBC)
• Chronic inflammatory conditions including inflammatory bowel disease

Critical Pitfalls to Avoid

Do not ignore an elevated neutrophil percentage (e.g., 84%) when total WBC is only mildly elevated—left shift can occur with normal WBC and still indicate bacterial infection. 1, 3

A normal WBC does not exclude bacterial infection, especially in elderly or immunosuppressed patients. 1, 3

Do not treat asymptomatic patients with antibiotics based solely on mildly elevated neutrophil counts without clinical context. 3

Serial measurements are more informative than single values for persistent unexplained elevation. 1

When to Suspect Hematologic Malignancy

Red flags requiring hematology referral: 3, 4

• Constitutional symptoms (fever, weight loss, bruising, fatigue)
• Splenomegaly or lymphadenopathy
• Concurrent abnormalities in red blood cells or platelets
• Extreme leukocytosis (>100,000/mm³ represents a medical emergency due to risk of cerebral infarction and hemorrhage) 3, 5

Special Consideration: Adult-Onset Still's Disease

In patients with marked leukocytosis and neutrophilia, consider adult-onset Still's disease: 50% have WBC >15×10⁹/L and 37% have >20×10⁹/L. 3