484. Clinical decision guideline for influenza testing in the Emergency Department
Session: Poster Abstract Session: Respiratory Infections: Influenza
Thursday, October 8, 2015
Room: Poster Hall
Background: Influenza presents with a varied range of respiratory symptoms and/or fever, which overlap with multiple other circulating respiratory pathogens.  In practice, timely and accurate diagnosis of influenza is essential however, for appropriate initiation of antiviral treatment in accordance with Centers for Disease Control and Prevention (CDC) guidelines.  Despite these treatment recommendations, there is no clear guidance on who should be tested for influenza.  We sought to derive and validate a clinical decision guideline (CDG), based on presenting signs and symptoms, to guide influenza testing decisions for emergency department (ED) patients with increased risk of influenza complications.

Methods: This is a prospective cohort study performed at 4 US EDs.  From November 2013 – April 2014 we enrolled adults who presented to the ED with acute respiratory illness, broadly defined as presence of at least one of the following symptoms within 7 days of ED presentation (cough, shortness of breath, change in sputum production, sinus pain, nasal congestion, rhinorrhea, sore throat, subjective fever or temperature > 38C). We included only those who would meet CDC criteria for antiviral treatment if influenza test resulted positive.  Subjects completed a structured symptom questionnaire and received influenza testing with gold-standard PCR.  The data was randomly split into a derivation (80%) and validation dataset (20%). Using a stepwise logistic regression, 4 independent variables were selected using the derivation set, and then analyzed using the validation set.

Results: Of 1987 enrolled subjects, 185 (9.3%) had influenza. The derived CDG included symptoms of cough (2 points), headache (1 point), subjective fever (1 point), and triage temperature of > 38 C (1 point) whereby any patient with 3 or greater points should be tested for influenza.  In the training set this CDG had a sensitivity of 93% and specificity of 39% for influenza.  In the validation set, this CDG had a sensitivity of 92% and specificity of 28%.

Conclusion: We derived and internally validated a highly sensitive CDG to inform influenza testing amongst ED patients who meet CDC treatment recommendations for receiving antiviral treatment during the influenza season (November – April); key symptoms include cough, headache, subjective fever, and documented fever.

Andrea Dugas, MD, PhD, Emergency Medicine, The Johns Hopkins University, Baltimore, MD and Richard Rothman, MD, PhD, Johns Hopkins Medical Institute, Baltimore, MD


A. Dugas, None

R. Rothman, None

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