Despite Caution, Rapid Influenza Diagnostic Test a Major Predictor of Treatment

Due to limited sensitivity, the Centers for Disease Control and Prevention (CDC) cautions clinicians not to rely on rapid influenza diagnostic test (RIDT) results when making influenza treatment decisions.¹ Despite this guidance, results from RIDT are a major predictor of a clinician’s decision to prescribe antiviral treatment, according to a study presented at IDWeek 2016.²

Since 2003, the New York State Department of Health’s Emerging Infections Program has conducted active population-based surveillance for all laboratory-confirmed hospitalized influenza cases in 15 counties in the Albany (n=8) and Rochester (n=7) regions.  While the Rochester region actively uses reverse transcription-polymerase chain reaction (RT-PCR) to test patients for influenza-like illness (ILI), the Albany region has continued to use RIDT. As part of the CDC’s Influenza-Associated Hospitalizations Surveillance Network (FluSurv-NET), the clinical laboratories in Albany are “encouraged to submit both RIDT positive and negative specimens for patients hospitalized with ILI to the Wadsworth Center  for PCR testing.”

Eva Pradhan, MPH, MHA, and colleagues from the New York State Department of Health reviewed data from all laboratory-confirmed hospitalized influenza patients from the 8 Albany counties using FluSurv-NET.

During the 2012-2013, 2013-2014, and 2014-2015 influenza seasons, 1992 patients identified with influenza were hospitalized. “Of these, 382 (19.2%) patients initially tested negative by RIDT at the hospital laboratory but later confirmed as PCR+ at Wadsworth Center,” the researchers noted. Use of antiviral treatment in patients testing negative for influenza on RIDT but found to be positive on PCR specimen testing at the Wadsworth Center was significantly lower when compared with positive RIDT and PCR testing (16% vs 85.2%, P <.001). A positive test result at the hospital laboratory was the most significant factor associated with patients receiving antiviral treatment during hospitalization.

“This analysis highlights the need for better clinician education about the limitations of RIDTs for treatment management decisions of influenza in both the hospital and community settings,” the researchers concluded.

Reference

1. Rapid influenza diagnostic tests. Centers for Disease Control and Prevention website. http://www.cdc.gov/flu/professionals/diagnosis/clinician_guidance_ridt.htm#interpretation. Updated October 25, 2016. Accessed November 15, 2016.
2. Pradhan E, McGuire S, Spina NL, et al. Use of rapid influenza diagnostic tests: impact on treatment of hospitalized influenza cases, New York – 2012-2015. Presented at: IDWeek 2016. New Orleans, LA; October 26-30, 2016. Poster 1274.