Use of a Combination Biomarker Algorithm to Identify Critically Ill ...

1505. Use of a Combination Biomarker Algorithm to Identify Critically Ill Surgical Patients With Suspected Sepsis at Very Low Likelihood of Bacterial Infection Jennifer Han, MD, MSCE1; Irving Nachamkin, DrPH, MPH, FIDSA2; Susan Coffin, MD, MPH, FPIDS3; Jeffrey S. Gerber, MD, PhD4; Charles Garrigan, MB2; Xiaoyan Han, MS5; Warren Bilker, PhD5; Jacqueleen Wise, BA5; Pam Tolomeo, MPH5; Ebbing Lautenbach, MD, MPH, MSCE, FIDSA, FSHEA1; for the Centers for Disease Control and Prevention (CDC) Prevention Epicenters Program1; 1Division of Infectious Diseases, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania; 2Department of Pathology and Laboratory Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania; 3 Department of Pediatrics, Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania; 4Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania; 5Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania

timepoints in patients with bacterial sepsis (figure 1b). A number of combinations of A2M and PCT, using varying cutoff values and measurement timepoints, demonstrated moderately high negative predictive values (72%-75%) while retaining moderate specificities (46%-50%) for diagnosing bacterial sepsis.

Session: 217. Antimicrobial Stewardship: Role of Diagnostics Saturday, October 10, 2015: 12:30 PM Background. Sepsis remains a diagnostic challenge in the intensive care unit (ICU). The use of biomarkers in differentiating bacterial sepsis from other causes of systemic inflammatory syndrome (SIRS) may be particularly useful in the surgical population, given the systemic inflammatory response that often follows major surgery. The goal of this study was to assess test characteristics of a number of biomarkers for identifying ICU patients with a very low likelihood of bacterial sepsis. Methods. A prospective cohort study was conducted in a surgical ICU of a university hospital. Patients with presumed bacterial sepsis were consecutively enrolled from February 2012 to April 2013. Concentrations of nine biomarkers (α-2 macroglobulin [A2M], C-reactive protein, ferritin, fibrinogen, haptoglobin, procalcitonin [PCT], serum amyloid A, serum amyloid P, and tissue plasminogen activator), were determined at baseline, 24 hours, 48 hours, and 72 hours after enrollment. The presence of bacterial sepsis was determined via medical record review by two infectious diseases trained physicians. Performance characteristics were calculated for varying combinations of biomarkers for discrimination of bacterial sepsis from other causes of SIRS. Results. Of 69 patients meeting inclusion criteria, 42 (61%) had documented bacterial sepsis and 27 (39%) had other causes of SIRS. The most common sources of bacterial sepsis were bloodstream (33%), intra-abdominal (27%), and pulmonary (19%). A2M values were significantly lower at all measured timepoints in patients with bacterial sepsis (figure 1a). Conversely, PCT values were significantly higher at all measured

Conclusion. Combinations of A2M and PCT demonstrated moderately high ability to discriminate bacterial sepsis from other causes of SIRS in surgical ICU patients. Future studies should focus on the use of these algorithms to improve antibiotic use in the critically ill surgical population. Disclosures. All authors: No reported disclosures.

Poster Abstracts

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OFID 2015:2 (Suppl 1)

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