Effect of the Influenza Virus Rapid Antigen Test on a Physician's Decision to Prescribe Antibiotics and on Patient Length of Stay in the Emergency Department

BACKGROUND Influenza virus infection is a common reason for visits to the emergency department (ED) during the influenza season. A rapid and accurate diagnosis of influenza virus infection is important to reduce unnecessary antibiotic prescription and to improve patient care. The aim of this study was to examine whether using the Influenza Virus Rapid Antigen Test (IVRAT) in the ED affects the decision to prescribe antibiotics or the length of hospital stay (LOS). METHODS Data from patients suffering from an influenza-like illness (ILI) and who were discharged after visiting the ED at Chungbuk National University Hospital were reviewed over two influenza seasons: 2010-2011, when IVRAT was not used in the ED, and 2011-2012, when it was. The numbers of antibiotic prescriptions issued and the ED LOS during these two seasons were then compared. RESULTS The number of antibiotic prescriptions was significantly lower in 2011-2012 (54/216, 25.0%) than in 2010-2011 (97/221, 43.9%; P<0.01). However, the median ED LOS for patients in 2011-2012 was much longer than that of patients in 2010-2011 (213 minutes vs. 257 minutes; P<0.01). During the 2011-2012 influenza season, 73 ILI patients showed a positive IVRAT result whereas 123 showed a negative result. Upon discharge, antibiotics were given to 42/123 (34.1%) ILI patients with a negative IVRAT result, but to only 7/73 (9.6%) patients with a positive IVRAT result (P<0.01). CONCLUSIONS Performing IVRAT in the ED reduced the prescription of antibiotics to ILI patients discharged after ED care. However, the ED LOS for patients who underwent IVRAT was longer than that for patients who did not. Thus, performing IVRAT in the ED reduces the unnecessary prescription of antibiotics to ILI patients during the influenza season.