School of Medicine

Background: While an elevated white blood cell count (WBC) is a widely utilized measure for evidence of infection and an important criterion for evaluation of systemic inflammatory response syndrome (SIRS), its component band count occupies a more contested position within clinical emergency medicine. Recent studies indicate that bandemia is highly predictive of a serious infection, suggesting that clinicians who do not appreciate the value of band counts may delay diagnosis or overlook severe infections. Objectives: Whereas previous studies focused on determining the quantitative value of the band count (i.e. determining sensitivity, threshold for bandemia, etc.), this study directs attention to patient-centered outcomes, hypothesizing that the degree of bandemia predisposes patients to subsequent negative clinical outcomes associated with underappreciated severe infections. Methods: This retrospective study of electronic medical records includes patients who initially presented to the Emergency Department (ED) with bandemia and were subsequently discharged from the ED. These patients were screened for repeat ED visits within 7 days and death within 30 days. Results: In patients with severe bandemia who were discharged from the ED, there was a 20.9% revisit rate at 7 days and a 4.9% mortality rate at 30 days, placing severely bandemic patients at 5 times significantly greater mortality compared to non-bandemic patients (p=0.032). Conclusion: Our review of patient outcomes suggests that the degree of bandemia, especially in the setting of concurrent tachycardia or fever, is associated with greater likelihood of negative clinical outcomes.