498. Rapid Influenza Testing May Lead to a Delay in Diagnosis and Treatment, and Poor Outcomes in Patients with Influenza in H1N1 Predominant Season
Session: Poster Abstract Session: Respiratory Infections: Influenza
Thursday, October 8, 2015
Room: Poster Hall
Background: Rapid influenza diagnostic tests may be used to help decide on treatment for influenza, but lack sensitivity, and have a low negative predictive value in patients likely to have influenza. A false negative rapid influenza diagnostic test may lead to delay in diagnosis which may delay treatment and lead to a poor clinical outcome.

Methods: A chart review was done for all patients, who initially had a negative rapid influenza test (TRU FLU®, Meridian Bioscience, Inc.), but subsequently had influenza infection confirmed by a positive influenza PCR (SimplexaTM Direct Flu A/B & RSV, Focus Diagnostics, Inc.), during the 2013-2014 influenza season, an H1N1 predominant season. Poor outcome was defined as requiring ventilator support, or extracorporeal membrane oxygenation (ECMO); or patient death.

Results: Thirty-six patients were found to have negative rapid influenza testing, but subsequently had influenza confirmed by PCR.  The mean age of the cohort was 56.5 years (14-88), and included 22 females and 14 males.  Twenty-four patients had comorbid conditions, and two were pregnant. Six patients required ventilator support, two required ECMO, and five died. An average delay of 20.04 hours occurred from the time of the negative rapid influenza to the positive PCR testing results. The mean delay in diagnosis for those with a good outcome, a poor outcome, and death were 16.02, 40.71, and 35.10 hours, respectively.  The mean delay in treatment from the time of the negative rapid influenza for those with a good outcome, a poor outcome, and death were 20.11, 53.13 and 50.10 hours, respectively.

Conclusion: Using a rapid influenza assay that lacks adequate sensitivity may lead to delays in diagnosis and treatment, which could contribute to poor clinical outcomes. 

Carolina Vasquez Prado, DO1,2, Kevin Mckim, MD2, Yashwant Chudasama, MS2 and Peter Ender, MD2, (1)Internal Medicine, St. Luke’s University Hospital and Health Network, Bethlehem, PA, (2)St. Luke’s University Hospital and Health Network, Bethlehem, PA

Disclosures:

C. Vasquez Prado, None

K. Mckim, None

Y. Chudasama, None

P. Ender, None

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