Evaluation of the respiratory NeuMoDx™ Flu A-B/RSV/SARS-CoV-2 Vantage and Alinity m Resp-4-Plex assays.

BACKGROUND: December 2021 witnessed an unprecedented increase in SARS-CoV-2 infections in addition to the circulation of influenza A and respiratory syncytial viruses (RSV). Due to increased testing demands for SARS-CoV-2, influenza, and RSV associated with the overall increase in symptomatic respiratory infections, there is an urgent need for multiplex, automated, and high throughput assays in the diagnostic laboratories. METHODS: We compared the performance of the NeuMoDx™ Flu A-B/RSV/SARS-CoV-2 Vantage and the Alinity m Resp-4-Plex to the standard of care influenza A, B, RSV, and SARS-CoV-2 assays used at the Johns Hopkins Microbiology Laboratory. A total of 181 remnant nasopharyngeal swab (NPS) specimens positive for influenza A (n = 29), influenza B (n = 34), RSV (n = 40), SARS-CoV-2 (n = 33), influenza A/RSV (n = 1), and negatives (n = 44) were tested by either or both assays. RESULTS: Both the NeuMoDx™ Flu A-B/RSV/SARS-CoV-2 Vantage and the Alinity m Resp-4-Plex assays showed 100% total agreement for all the tested analytes. For samples with available cycle threshold (Ct) values, comparable ranges were noted for all targets between the two assays and to the standard of care Ct values as well. CONCLUSION: The NeuMoDx™ Flu A-B/RSV/SARS-CoV-2 Vantage and the Alinity m Resp-4-Plex assays showed high sensitivity and accuracy for all the analytes included in both tests. Implementing these assays will assist the diagnostic laboratories with the surge of testing during the 2021-2022 influenza season.

Multicenter evaluation of the NeuMoDx™ SARS-CoV-2 Test.

The SARS-CoV-2 virus has caused millions of confirmed COVID-19 cases worldwide and hundreds of thousands of deaths in less than 6 months. Mitigation measures including social distancing were implemented to control disease spread, however, thousands of new cases continue to be diagnosed daily. To resume some suspended social activities, early diagnosis and contact tracing are essential. To meet this required diagnostic and screening capacity, high throughput diagnostic assays are needed. The NeuMoDx™ SARS-CoV-2 assay, performed on a NeuMoDx molecular system, is a rapid, fully automated, qualitative real-time RT-PCR diagnostic test with throughput of up to 288 tests in an 8 -h shift. The assay received emergency use authorization from the FDA and is used in some large testing centers in the US. This paper describes the analytical and clinical performance of the assay at three centers: Johns Hopkins Hospital, St. Jude Children's Research Hospital, and the Wadsworth Center.

Comparing the analytical performance of three SARS-CoV-2 molecular diagnostic assays.

In December 2019, a novel coronavirus (SARS-CoV-2) was first isolated from Wuhan city, China and within three months, the global community was challenged with a devastating pandemic. The rapid spread of the virus challenged diagnostic laboratories to rapidly develop molecular diagnostic methods. As SARS CoV-2 assays became available for testing on existing molecular platforms, laboratories devoted unprecedented energy and resources into evaluating the analytical performance of the new tests and in some cases developed their own diagnostic assays under FDA-EUA guidance. This study compares the validation of three different molecular assays at the Johns Hopkins Molecular Virology laboratory: the RealStar® SARS-CoV-2 RT-PCR, ePlex® SARS-CoV-2, and the CDC COVID-19 RT-PCR tests. Overall, our studies indicate a comparable analytical performance of the three assays for the detection of SARS-CoV-2.

Comparison of automated and manual nucleic acid extraction methods for detection of enterovirus RNA.

Automated nucleic acid extraction is an attractive alternative to labor-intensive manual methods. We compared two automated methods, the BioRobot M48 instrument (Qiagen, Inc.) and MagNA Pure (Roche Applied Sciences) methods, to two manual methods, the QIAamp Viral RNA Mini kit (Qiagen) and TRIzol (Invitrogen), for the extraction of enterovirus RNA. Analytical sensitivity was assessed by dilution analysis of poliovirus type 2 Sabin in cerebrospinal fluid. The sensitivity of PCR was equivalent after RNA extraction with QIAamp, BioRobot M48, and MagNA Pure. All 18 replicates of 100 PFU/ml were detected after extraction by the four methods. Fewer replicates of each successive dilution were detected after extraction by each method. At 10(-1) PFU/ml, 17 of 18 replicates were positive by QIAamp, 15 of 18 replicates were positive by BioRobot M48, and 12 of 18 replicates were positive by MagNA Pure; at 10(-2) PFU/ml, 4 of 17 replicates were positive by QIAamp, 2 of 18 replicates were positive by BioRobot M48, and 0 of 18 replicates were positive by MagNA Pure. At 10(-3) PFU/ml, no replicates were detected. Evaluation of TRIzol was discontinued after nine replicates due to a trend of lower sensitivity (at 10(-3) PFU/ml eight of nine replicates were positive at 100 PFU/ml, four of nine replicates were positive at 10(-1) PFU/ml, and zero of nine replicates were positive at 10(-2) PFU/ml). Concordant results were obtained in 24 of 28 clinical specimens after extraction by all methods. No evidence of contamination was observed after extraction by automated instruments. The data indicate that the sensitivity of enterovirus PCR is largely similar after extraction by QIAamp, BioRobot M48, and MagNA Pure; a trend of decreased sensitivity was observed after TRIzol extraction. However, the results of enterovirus PCR were largely concordant in patient samples, indicating that the four extraction methods are suitable for detection of enteroviruses in clinical specimens.