Factors influencing sensitivity of a rapid influenza diagnostic test in a community-based population of kindergarten through 12th-grade students: Wisconsin 2015-2020.

Abstract

Rapid influenza diagnostic tests (RIDTs) have variable sensitivity. In a community-based population of kindergarten through 12th-grade (K-12) students, we assessed factors that may influence RIDT performance using 2368 paired results from Sofia® influenza A + B fluorescent immunoassay and reverse transcription polymerase chain reaction (RT-PCR). RIDT sensitivity and specificity were 76.1% (95% CI: 72.8-79.1) and 97.2% (96.2-97.9), respectively. Factors associated with sensitivity included runny nose (OR =3.0, p< 0.001), nasal congestion (1.59, p= 0.045), days from symptom onset (per day; 0.75; p< 0.001), myalgia (0.61; p= 0.014), age (per 5years; 0.55; p= 0.001), and detection of another virus (0.50; p= 0.043). Understanding these factors can aid in interpreting negative results.