Multi-center evaluation of the adenovirus R-gene US assay for the detection of adenovirus in respiratory samples

Background: Adenoviruses (AdV) cause a variety of upper and lower respiratory tract infections, with the potential for severe outcomes, especially in persons with immune suppression or other underlying diseases. The ADENOVIRUS US R-gene (AdV R-gene, Argene/bioMérieux) is a FDA cleared real-time PCR assay that utilizes primers and fluorescent probes that target a conserved region of the hexon gene and an internal control DNA.

Objectives: This prospective multi-center study evaluated the clinical performance of AdV R-gene for AdV detection in respiratory specimens from symptomatic patients of all ages.

Study design: Nucleic acids from nasopharyngeal washes/aspirates (NPW/A; n=393) and NP flocked swabs (NPS, Copan) (n=1183) were extracted using NucliSENS easyMAG (bioMérieux) and AdV R-gene PCR was performed using the SmartCycler (Cepheid). AdV R-gene results were compared to R-Mix culture (Quidel/Diagnostic Hybrids). For a subset of samples (n=946) AdV R-gene and R-Mix results were also compared to A549 cell culture.

Results: In first intention analysis for NPS the AdV R-gene positive percent agreement (PPA), and negative percent agreement (NPA) were 91.7% and 96.2%, respectively, and for NPW/A were 100% and 94.4%, respectively, compared to R-Mix culture. In second intention analysis, discordant samples only were tested with an AdV real-time PCR assay (Viracor-IBT Labs) and amplicon sequencing. For NPS, the sensitivity, specificity, PPV and NPV for AdV R-gene were 98.9%, 100%, 100%, and 99.9%, respectively and for R-Mix culture were 51.7%, 99.7%, 93.8%, and 96.3%, respectively. For NPW/A, the sensitivity, specificity, PPV and NPV for AdV R-gene were 100%, 99.7%, 97.6%, and 100%, respectively, and for R-Mix culture were 52.5%, 100%, 100%, and 94.9%, respectively. Overall, AdV was detected by AdV R-gene and R-Mix in 7.4% and 4.1% NPS, respectively, and in 10.7% and 5.3% NPW/A, respectively. Children 5yr and younger had the highest rates of AdV infections. In a subset of specimens (n=946) the sensitivity of AdV R-gene, R-Mix, and A549 cell culture were 95.0%, 55.4% and 66.3%.

Conclusions: AdV R-gene is sensitive and specific for the detection of AdV in NPW/A and NPS samples. AdV R-gene is simple to use and provides a rapid time to results (within 2.5-3h).