A 58-year-old female presents with a 3-day history of productive cough, fever of 101.4°F, and pleuritic chest pain. Her CBC reveals a WBC of 14,800/μL with 82% neutrophils and 5% bands. Which interpretation of the WBC best fits this clinical picture?

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Accepted Answer

✅ A. Neutrophilic leukocytosis with a left shift, consistent with acute bacterial infection
The normal WBC range is 4,500–11,000/μL. A WBC of 14,800/μL is elevated (leukocytosis), and the predominance of neutrophils (>70%) with bands >3% defines a "left shift," which classically points to an acute bacterial process such as community-acquired pneumonia. The clinical context of fever, productive cough, and pleuritic chest pain strongly supports this interpretation.

❌ B. Normal WBC count for an adult female
A WBC of 14,800/μL is above the 11,000/μL upper limit and is not normal. This answer would only apply if the total WBC fell between 4,500 and 11,000/μL with a balanced differential.

❌ C. Leukopenia suggestive of bone marrow suppression
Leukopenia is defined as WBC <4,500/μL and would suggest chemotherapy effect, viral suppression, or marrow failure. This patient has the opposite problem—leukocytosis—so this interpretation is inappropriate.

❌ D. Lymphocytic leukocytosis suggestive of viral infection
Viral infections typically produce a lymphocyte-predominant elevation (>40–50% lymphocytes). This patient's differential is neutrophil-predominant, so a viral pattern does not fit.

:::important
Normal adult WBC: 4,500–11,000/μL. Neutrophils >70% plus bands >3% equals a left shift—treat as bacterial until proven otherwise.
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