Factors associated with real time RT-PCR cycle threshold values among medically attended influenza episodes.

Spencer S1,2, Clippard J1,2, Thompson M1, Piedra PA3,4, Jewell A3, Avadhanula V3, Mei M3, Jackson ML5, Meece J6, Sundaram M6, Belongia EA6, Cross R7,Johnson E7, Bullotta A8, Rinaldo C8, Gaglani M9, Murthy K9, Clipper L9, Berman L1, Flannery B1.

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Abstract

We evaluated the cycle threshold (CT) values of 1160 influenza A positive and 806 influenza B positive specimens from two seasons of the US Flu VE Network to identify factors associated with CT values. Low CT values (high genomic load) were associated with shorter intervals between illness onset and specimen collection, young age (ages 3-8 years old), and self-rated illness severity for both influenza A and B. Low CT values were also associated with reported fever/feverishness and age ≥65 years for influenza A. This article is protected by copyright. All rights reserved.