title: Diagnostic performance of a biomarker panel as a negative predictor for acute appendicitis in adult ED patients with abdominal pain.
abstract: OBJECTIVE
  Evaluate the diagnostic accuracy of the APPY1TM biomarker panel, previously described for use in pediatric patients, for identifying adult ED patients with abdominal pain who are at low risk of acute appendicitis.
  
  
  METHODS
  This study prospectively enrolled subjects >18years of age presenting to seven U.S. emergency departments with <72hours of abdominal pain suggesting possible acute appendicitis. The APPY1 panel was performed on blood samples drawn from each patient at the time of initial evaluation and results were correlated with the final diagnosis either positive or negative for acute appendicitis.
  
  
  RESULTS
  431 patients were enrolled with 422 completing all aspects of the study. The APPY1 biomarker panel exhibited a sensitivity of 97.5% (95% CI, 91.3-99.3%), a negative predictive value of 98.4% (95% CI, 94.4-99.6%), a negative likelihood ratio of 0.07 (95% CI, 0.02-0.27), with a specificity of 36.5% (95% CI, 31.6-41.8%) for acute appendicitis. The panel correctly identified 125 of 342 (36.6%) patients who did not have appendicitis with 2 (2.5%) false negatives. The CT utilization rate in this population was 72.7% (307/422). Of 307 CT scans, 232 were done for patients who did not have appendicitis and 79 (34%) of these patients were correctly identified as negative with "low risk" biomarker panel results, representing 26% (79/307) of all CT scans performed.
  
  
  CONCLUSIONS
  This biomarker panel exhibited high sensitivity and negative predictive value for acute appendicitis in this prospective adult cohort, thereby potentially reducing the dependence on CT for the evaluation of possible acute appendicitis.
authors.affiliation: Division of Emergency Medicine, Newton-Wellesley Hospital, Newton, MA, United States. Electronic address: dhuckins@partners.org.
authors.forename: David S
authors.initials: DS
authors.lastname: Huckins
authors.affiliation: Boulder Statistics, LLC, Boulder, CO, United States.
authors.forename: Karen
authors.initials: K
authors.lastname: Copeland
authors.affiliation: Vanderbilt University School of Medicine, Nashville, TN, United States.
authors.forename: Wesley
authors.initials: W
authors.lastname: Self
authors.affiliation: University of California Davis, Sacramento, CA, United States.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Vance
authors.affiliation: University of Florida College of Medicine, Jacksonville, FL, United States.
authors.forename: Phyllis
authors.initials: P
authors.lastname: Hendry
authors.affiliation: Medical University of South Carolina, Charleston, SC, United States.
authors.forename: Keith
authors.initials: K
authors.lastname: Borg
authors.affiliation: Venaxis, Inc., Castle Rock, CO, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Gogain
mesh_terms: D015746:Abdominal Pain / Q000175:diagnosis* / Q000000981:diagnostic imaging; D000328:Adult; D001064:Appendicitis / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D009194:Myeloma Proteins / Q000032:analysis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D014481:United States
chemical_list: D015415:Biomarkers; D009194:Myeloma Proteins; D002097:C-Reactive Protein
keywords: Adult; Appendicitis; Biomarker; Computed tomography; Diagnostic accuracy; Sensitivity