Comparison of the Cepheid Xpert Xpress Flu/RSV assay and commercial real-time PCR for the detection of influenza A and influenza B in a prospective cohort from China

Abstract

Background: The Xpert Xpress Flu/RSV assay is released by FDA for rapid detection of influenza A (FluA), influenza B (FluB), and respiratory syncytial virus (RSV). This study aimed to evaluate its clinical performance in comparison to that of the RT-PCR assay cleared by China FDA (CFDA-PCR). Methods: Nasopharyngeal specimens were collected from patients and tested by the two assays side by side. Discordant results were tested with a laboratory-developed real-time PCR for resolution. Viral load in the sample was quantified with a droplet digital PCR. Results: A total of 658 specimens were involved and gave 94.7%-99.1% agreement between the two assays. The Xpert assay showed higher sensitivity for FluA (100% vs. 89.8%) and FluB detection (100% vs. 95.3%), and also higher accuracy (98.9% vs. 95.7%) for FluA than the CDFA-PCR. The positive and negative predictive values (NPV) for the three viruses ranged from 90.5% to 100% in the two assays, with higher NPV for FluA and FluB in Xpert assay. Moreover, the Xpert Ct values showed a linear correlation with virus titer in specimens tested. Conclusion: Overall, the Xpert assay is a reliable and sensitive tool for the detection of FluA, FluB and RSV in our clinical settings.

Viral load of SARS-CoV-2 across patients and compared to other respiratory viruses

“…For Influenza A and B and RSV the Xpert® Xpress Flu/RSV was used and converted to viral load according to Zou et al. [ 7 ]. Only nasopharyngeal and nose swabs were included.…”

Severity and mortality of respiratory syncytial virus vs influenza A infection in hospitalized adults in China

“…Respiratory syncytial virus and influenza A virus infection were confirmed by analysis of nasopharyngeal swabs, sputum, bronchoalveolar lavage fluid and/or blood and/or urine samples using RSV Nucleic Acid Detection Kit (Liferiver) and Influenza A Virus Nucleic Acid Detection kit (Liferiver), respectively 15 …”

Viral load in upper respiratory tract of COVID-19 patients detected by digital PCR

“…Bio-Rad QX200 Droplet Generator was used to produce droplets, which were transferred to a 96-well PCR plate for RT-PCR ampli cation following the reaction conditions: reverse transcription at 45 °C for 60 min, enzyme activation at 95 °C for 10 min, 40 cycles of denaturation at 95 °C for 30 s and annealing/extension at 58 °C for 1 min, followed by enzyme deactivation at 98 °C for 10 min and hold at 4 °C. Fluorescence signal of each droplet was subsequently read and analyzed using Bio-Rad OX200 Droplet Reader [17].…”

“…using the Viral Total Nucleic Acid Extraction kit (HEAS BioTech, Guangzhou, China) in the SMART32 system (Liferiver, Shanghai, China) following their instruction manuals [17]. A total of 200 μl volume of each samples were used for the extraction.…”