Performance analysis of the GeneXpert respiratory panel prototype assay for the diagnosis of viral and bacterial upper respiratory tract infections

TL;DR

The study evaluates a new diagnostic test for respiratory infections and finds it performs as well as existing FDA-approved tests.

Contribution

The paper provides early real-world performance data for a new respiratory pathogen detection assay.

Findings

The GX-RP assay showed 92.1% concordance with existing FDA-approved tests.

GX-RP had a 93.1% positive percent agreement and 99.9% negative percent agreement.

Codetections were present in 60.9% of discordant results.

Abstract

GeneXpert respiratory panel (GX-RP) is a new in vitro qualitative multiplexed nucleic acid amplification test designed to simultaneously detect and identify 26 common respiratory pathogens from nasopharyngeal swabs (NPSs) in patients exhibiting signs and symptoms of upper respiratory tract infection. This is a retrospective study that compares the prototype assay with two FDA-approved respiratory panels—the BioFire FilmArray (FA) Respiratory 2.1 plus and Hologic Panther Fusion (PF) respiratory assay. A total of 292 NPS specimens from patients with upper respiratory tract infection symptoms were collected from three hospitals in Hong Kong, SAR. There was concordance in 269/292 specimens (92.1%), reaching full agreement with Influenza A, Bordetella pertussis, and Mycoplasma pneumoniae. Among the discordant specimens, 7 specimens were only positive for GX-RP, and 16 specimens were only positive for their comparators. Codetections were present in 60.9% of the discordant results. GX-RP has an overall positive percent agreement of 93.1%, negative percent agreement of 99.9%, and a prevalence-adjusted bias-adjusted kappa of 99.0%. It showed good agreement when compared with FA respiratory panel or PF respiratory assay.

Multiplex respiratory pathogen panels are a diagnostic mainstay in patients with upper respiratory tract symptoms. New platforms and improved versions of previous platforms emerge over time. Early evaluation of their diagnostic performance using real-world data is essential for the necessary revisions to be made, which would facilitate public access to improved panels. Our retrospective study provides preliminary evidence that the GeneXpert respiratory panel prototype assay has comparable performance to the BioFire FilmArray and Hologic Panther Fusion respiratory assays and may be an additional candidate in our future toolkit against upper respiratory tract pathogens.

Figures