From the Guidelines
The management of elevated segmented neutrophils (segs) on a differential count should focus on identifying and treating the underlying cause, with a thorough history and physical examination being the first step. When encountering elevated segs, the clinician should consider potential causes such as bacterial infections, inflammation, tissue injury, stress, or certain medications. Common infectious causes include pneumonia, urinary tract infections, cellulitis, and abscess formation. Laboratory tests should include a complete blood count with differential, inflammatory markers (ESR, CRP), blood cultures if infection is suspected, and targeted diagnostic tests based on clinical presentation 1. Imaging studies may be warranted depending on symptoms. If an infection is identified, appropriate antimicrobial therapy should be initiated based on the suspected pathogen and site of infection, with the duration of therapy dictated by the particular organism and site, and continued until there are clear signs of marrow recovery or the neutrophil count exceeds 500 cells/mm3 1. For non-infectious inflammatory conditions, treating the underlying disorder (such as with anti-inflammatory medications for autoimmune diseases) is appropriate. Neutrophilia due to medications typically resolves with discontinuation of the offending agent. Persistent unexplained neutrophilia warrants hematology consultation to rule out myeloproliferative disorders. The elevated neutrophil count itself typically normalizes once the underlying condition is adequately addressed, as neutrophilia represents the body's appropriate immune response to various stimuli rather than a primary disorder in most cases. Key considerations in the management of elevated segs include:
- Identifying the underlying cause through thorough history, physical examination, and laboratory tests
- Initiating appropriate antimicrobial therapy for infections, with consideration of the duration of therapy and the patient's neutrophil count
- Treating non-infectious inflammatory conditions and discontinuing offending medications
- Consulting hematology for persistent unexplained neutrophilia to rule out myeloproliferative disorders, as recommended by recent guidelines 1.
From the Research
Management Approach for Elevated Segmented Neutrophils
Elevated segmented neutrophils (segs) on a differential count can indicate various conditions, including infections, inflammatory diseases, or other medical emergencies. The management approach for a patient with elevated segs depends on the underlying cause.
Diagnostic Considerations
- A high neutrophil count can be associated with bacterial infections, as seen in studies 2, 3.
- The neutrophil-lymphocyte count ratio (NLCR) has been shown to be a predictor of bacteremia in adult patients admitted to the Emergency Department 3.
- Lymphocytopenia, or a low lymphocyte count, can also be a predictor of bacteremia 3.
- The complete blood cell count (CBC) and differential can be useful in diagnosing late-onset sepsis in infants 4.
Clinical Implications
- Elevated segs can indicate sepsis, which requires prompt medical attention and treatment.
- The presence of immature neutrophils (bands) in the circulating blood can be used as a clinical indicator of sepsis 2.
- A band count greater than 10% can be used as a diagnostic criterion for systemic inflammatory response syndrome (SIRS) 2.
Laboratory Tests
- A complete blood cell count (CBC) with differential can help diagnose and monitor conditions associated with elevated segs.
- Other laboratory tests, such as C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR), can also be useful in diagnosing and monitoring inflammatory conditions 5.