Is a Neutrophil Count of 11.4 High?
Yes, a neutrophil count of 11.4 × 10^9/L (or 11,400 cells/mm³) is moderately elevated and warrants clinical evaluation for underlying causes, particularly bacterial infection, though it does not reach the threshold that carries the highest likelihood of serious infection. 1, 2
Understanding the Elevation
Normal neutrophil range in healthy individuals after the first few days of life is approximately 1,350 to 8,840 cells/mm³ (1.35-8.84 × 10^9/L), making your count of 11.4 clearly above normal. 3
The threshold for high concern is a total white blood cell count ≥14,000 cells/mm³, which has a likelihood ratio of 3.7 for bacterial infection. 2, 4 Your count of 11.4 is elevated but below this critical threshold.
This level alone does not automatically indicate infection without accompanying clinical signs such as fever, localized pain, or systemic symptoms. 1, 2
What Could Cause This Elevation?
Infectious Causes (Most Common)
- Bacterial infections are the most frequent cause of neutrophilia, including respiratory tract infections, urinary tract infections, skin/soft tissue infections, and gastrointestinal infections. 2
Non-Infectious Causes
- Physiologic stress responses such as recent surgery, trauma, burns, or myocardial infarction can elevate neutrophils. 1
- Inflammatory conditions like vasculitis or inflammatory bowel disease. 1
- Medications including corticosteroids, lithium, beta-agonists, and G-CSF. 1, 2
- Malignancy, particularly myeloproliferative disorders, can cause persistently elevated counts. 1
What You Should Look For Clinically
Assess for these specific markers that indicate bacterial infection:
- Absolute band count ≥1,500 cells/mm³ (likelihood ratio 14.5 - the most powerful predictor). 2, 4
- Neutrophil percentage >90% (likelihood ratio 7.5). 2, 4
- Left shift ≥16% band neutrophils (likelihood ratio 4.7, even with normal total WBC). 2, 4
- Fever, hypotension, tachycardia, tachypnea, or altered mental status suggesting sepsis. 4
Recommended Diagnostic Approach
If symptomatic (fever, localized pain, systemic signs):
- Obtain a manual differential count to assess for left shift and absolute band count. 2, 4
- Perform blood cultures if systemic infection is suspected. 2, 4
- Order site-specific cultures and imaging based on symptoms (chest X-ray for respiratory symptoms, urinalysis for urinary symptoms). 2, 4
- Check CRP or lactate if sepsis is a concern. 4
If asymptomatic:
- Review medication list for drugs that cause neutrophilia (corticosteroids, G-CSF, lithium, beta-agonists). 1, 2
- Review recent medical history for physiologic stressors (recent surgery, trauma, MI). 1
- Routine monitoring may be sufficient without immediate intervention if no clinical signs of infection or inflammation are present. 1
Critical Pitfalls to Avoid
- Do not ignore this elevation when total WBC is only mildly elevated, as left shift can occur with normal or near-normal WBC and still indicate bacterial infection. 2
- Do not treat asymptomatic patients with antibiotics based solely on this mildly elevated neutrophil count without other evidence of infection. 2
- Do not overlook the significance of absolute neutrophil count elevation even when it's below 14,000 cells/mm³. 2