Is a high neutrophil (neut) percentage of 84.0 common in patients on long-term low-dose prednisone (corticosteroid) therapy of 7.5 milligrams daily?

Neutrophil Percentage of 84% on Long-Term Low-Dose Prednisone

Yes, a neutrophil percentage of 84% is a common and expected finding in patients on long-term low-dose prednisone therapy at 7.5 mg daily, representing a predictable pharmacologic effect of corticosteroid-induced neutrophilia rather than a pathologic process. 1

Mechanism and Expected Findings

Corticosteroid-induced leukocytosis occurs through neutrophil demargination and delayed apoptosis, producing a characteristic pattern of elevated neutrophil percentage without left shift or toxic granulation. 1

• Even small doses of prednisone (as low as 2.5 mg) administered over prolonged periods can induce extreme and persistent leukocytosis, with neutrophils comprising the predominant cell type 1, 2
• The neutrophilia from low-dose prednisone (7.5 mg daily) produces systemic effects comparable to higher doses, with sustained elevation in neutrophil percentages 2
• Prednisone at doses of 5-80 mg produces mean neutrophil increases of approximately 4,000-4,600 cells/mm³, with the percentage of neutrophils rising proportionally 3

Temporal Pattern

• Leukocytosis can appear as early as the first day of treatment and persist for the entire duration of therapy 1
• Maximal leukocytosis typically occurs within two weeks of initiating treatment, after which the white blood cell count may decrease slightly but does not return to pretreatment levels 1
• The effect remains stable during chronic administration, making an 84% neutrophil percentage entirely consistent with long-term therapy 1

Distinguishing from Infection

The critical distinction between corticosteroid-induced neutrophilia and infection-related neutrophilia lies in the absence of left shift and toxic granulation with steroid use. 1

Key Differentiating Features:

• Corticosteroid effect: Elevated neutrophil percentage WITHOUT left shift (band forms <6%), WITHOUT toxic granulation, and typically accompanied by eosinopenia, monocytosis, and variable lymphopenia 1
• Bacterial infection: Elevated neutrophil percentage (>90%) WITH left shift (band forms ≥16% or absolute band count ≥1,500/mm³), often with toxic granulation 4, 5

Diagnostic Algorithm for Elevated Neutrophils on Prednisone:

1. Obtain manual differential count (automated analyzers may miss subtle left shift) 5
2. Assess band neutrophil percentage:
   • <6% bands = likely corticosteroid effect 1
   • ≥16% bands = concerning for infection despite prednisone 4, 5
3. Evaluate absolute band count if available:
   • <1,500 cells/mm³ = consistent with steroid effect 5
   • ≥1,500 cells/mm³ = highest likelihood ratio (14.5) for bacterial infection 4, 5
4. Look for toxic granulation: Present in infection, rare in steroid-induced neutrophilia 1
5. Check accompanying cell lines:
   • Eosinopenia + monocytosis = supports steroid effect 1
   • Normal eosinophils without monocytosis = less typical for pure steroid effect 1

Clinical Context Considerations

• In patients on long-term prednisone with suspected infection, a left shift (>6% bands) and toxic granulation assist in differential diagnosis, as these findings are rare with corticosteroid-induced leukocytosis alone 1
• The presence of fever, elevated total band count (>1,500/mm³), or neutrophil percentage >90% warrants investigation for bacterial infection even in patients on chronic corticosteroids 4
• Procalcitonin levels may more appropriately reflect infection resolution compared to traditional inflammatory markers like CRP in patients receiving glucocorticoids 6

Important Caveats

• Do not dismiss infection based solely on chronic prednisone use: Immunocompromised patients on corticosteroids remain at risk for serious infections, and the baseline elevated neutrophil count can mask or delay recognition of superimposed infection 1
• Manual differential is essential: Automated analyzers cannot reliably distinguish between mature neutrophils and band forms, potentially missing clinically significant left shifts 5
• Medications beyond corticosteroids (lithium, beta-agonists, epinephrine) can also cause neutrophilia with left shift and should be considered in the differential 5
• Myelodysplastic syndromes can present with left shift as a dysplastic feature, though this would be unusual as an isolated finding in a patient with known prednisone use 5

Practical Management

For a patient on 7.5 mg prednisone daily with neutrophil percentage of 84% and no clinical signs of infection, no intervention is required—this represents expected drug effect. 1, 2

• Continue routine monitoring as clinically indicated
• Educate patients that elevated white blood cell counts are expected with chronic corticosteroid therapy 1
• Maintain high index of suspicion for infection based on clinical symptoms rather than baseline neutrophil elevation 1
• If infection is suspected, obtain manual differential to assess for left shift and toxic granulation before attributing neutrophilia solely to prednisone 1, 5