729. Improved Detection of Adenovirus with the FilmArray Respiratory Panel 2 Panel in a Pediatric Population

BACKGROUND: Human adenovirus (ADV) respiratory infections are associated with up to 8% of all identified viral causes of acute respiratory illnesses, especially among young children. They are therefore included as part of multiplex syndromic respiratory testing. Earlier versions of the FilmArray Respiratory Panel were targeted to genogroups B, C, and E. However, all adenovirus genogroups are associated with disease particularly in immunocompromised patients. Recently, a new version of the FilmArray Respiratory Panel 2 (RP2) has been FDA cleared with significant modifications to the adenovirus assay. The goal of this study was to compare the RP2 adenovirus assay to that of the previous version (RP1.7) and our laboratory-developed (LD) adenovirus PCR. METHODS: Analytical comparison: Ten stocks of know adenovirus serotypes representing genogroups A-F were diluted in M4 media and tested on RP2, RP1.7 and LD PCR to determine the relative limits of detection (LOD). Clinical comparison: A total of 423 pediatric nasopharyngeal samples were tested using RP2, RP1.7, adenovirus LD PCR. In addition we performed genotyping PCRs on most adenovirus positive samples based on the availability. RESULTS: Analytical evaluation revealed that for the 10 serotypes (18, 32, 7, 14, 5, 6, 20, 29, 4 and 40), RP2 showed at least 100-fold increase in sensitivity for six serotypes representing genogroups A, D and F. For B, C and E, the relative LODs were comparable. In the 423 clinical samples, there was an overall agreement of 94% between RP2 and RP1.7. Among those RP2+/RP1.7− samples (n = 20), 17 samples were confirmed ADV positive by LD PCR. They all had low viral burden (Ct values >30), among them nine samples had sole detections of adenovirus types A, D and F. Five samples were RP2-/RP1.7+, two samples were confirmed by LD PCR and both were type C. Overall, there was a 22% increase in Adenovirus with RP2 compared with RP1.7. CONCLUSION: The RP2 adenovirus assay has enhanced inclusivity and lower LOD for all adenovirus genogroups in comparison to RP1.7. Coupled with its faster run time and additional targets, RP2 represents a significant improvement for the syndromic detection of respiratory infections. DISCLOSURES: A. Leber, Nationwide Children’s Hospital: Research Contractor, Research support.