January 10, 2020
Authors of a new study have used their findings to develop a clinical decision guideline for influenza testing. The guideline was formulated in an effort to aid clinicians in determining which adult emergency department (ED) patients, who are eligible to receive antiviral treatment, should be tested for influenza.
“An accurate diagnosis of influenza is essential for appropriate antiviral treatment, in accordance with Centers for Disease Control and Prevention (CDC) guidelines. However, no clear guidance exists on which patients should be tested,” the researchers wrote.
From November 2013 to April 2014, the study authors enrolled 1941 adult patients with fever or respiratory symptoms from 4 US EDs. To be eligible for enrollment, the patients also had to meet criteria for antiviral treatment, as described in the 2013 CDC guidelines.
After testing all of the participants for influenza using polymerase chain reaction, the researchers determined that 183 of the participants (9.4%) had influenza.
The data was randomly segmented into 2 data sets—80% into a derivation set and 20% into a validation set.
“A discrete set of independent variables was selected by logistic regression, using the derivation set to create a scoring system, with a target sensitivity of at least 90%,” the authors wrote. “The derived [guideline] was then validated.”
The derived guideline includes new or increased cough (2 points), headache (1 point), subjective fever (1 point), and triage temperature of more than 100.4°C (1 point). According to the researchers, an individual with a score of 3 or more should be tested for influenza.
In the derivation set, the guideline had a sensitivity of 94.1% and a specificity of 36.6%. In the validation set, the guideline had a sensitivity of 91.5% and a specificity of 34.6%.
“A [clinical decision guideline] with high sensitivity was derived and validated,” the researchers concluded. “Incorporation into practice could standardize testing for high-risk patients in adult EDs during influenza seasons, potentially improving diagnoses and treatment.”
Dugas AF, Hsieh YH, LoVecchio F, et al; Emergency Department National Influenza Network Investigators. Derivation and validation of a clinical decision guideline for influenza testing in 4 US emergency departments. Clin Infect Dis. 2020;70(1):49-58. https://doi.org/10.1093/cid/ciz171.