Comparison of Two Commercial Molecular Tests and a Laboratory-Developed Modification of the CDC 2019-nCoV Reverse Transcriptase PCR Assay for the Detection of SARS-CoV-2.

We compared the ability of 2 commercial molecular amplification assays (RealTime SARS-CoV-2 on the m2000 [abbreviated ACOV; Abbott] and ID Now COVID-19 [abbreviated IDNOW; Abbott]) and a laboratory-developed test (modified CDC 2019-nCoV reverse transcriptase PCR [RT-PCR] assay with RNA extraction by eMag [bioMérieux] and amplification on QuantStudio 6 or ABI 7500 real-time PCR system [abbreviated CDC COV]) to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in upper respiratory tract specimens. Discrepant results were adjudicated by medical record review. A total of 200 nasopharyngeal swab specimens in viral transport medium (VTM) were collected from symptomatic patients between 27 March and 9 April 2020. Results were concordant for 167 specimens (83.5% overall agreement), including 94 positive and 73 negative specimens. The ACOV assay yielded 33 additional positive results, 25 of which were also positive by the CDC COV assay but not by the IDNOW assay. In a follow-up evaluation, 97 patients for whom a dry nasal swab specimen yielded negative results by IDNOW had a paired nasopharyngeal swab specimen collected in VTM and tested by the ACOV assay; SARS-CoV-2 RNA was detected in 13 (13.4%) of these specimens. Medical record review deemed all discrepant results to be true positives. The IDNOW test was the easiest to perform and provided a result in the shortest time but detected fewer cases of COVID-19. The ACOV assay detected more cases of COVID-19 than the CDC COV or IDNOW assays.

Moore NM ，Li H ，Schejbal D ，Lindsley J ，Hayden MK ... -  《-》

Performance of Abbott ID Now COVID-19 Rapid Nucleic Acid Amplification Test Using Nasopharyngeal Swabs Transported in Viral Transport Media and Dry Nasal Swabs in a New York City Academic Institution.

The recent emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has posed formidable challenges for clinical laboratories seeking reliable laboratory diagnostic confirmation. The swift advance of the crisis in the United States has led to Emergency Use Authorization (EUA) facilitating the availability of molecular diagnostic assays without the more rigorous examination to which tests are normally subjected prior to FDA approval. Our laboratory currently uses two real-time reverse transcription-PCR (RT-PCR) platforms, the Roche Cobas SARS-CoV2 and the Cepheid Xpert Xpress SARS-CoV-2. The two platforms demonstrate comparable performances; however, the run times for each assay are 3.5 h and 45 min, respectively. In search for a platform with a shorter turnaround time, we sought to evaluate the recently released Abbott ID Now COVID-19 assay, which is capable of producing positive results in as little as 5 min. We present here the results of comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media and comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media for Cepheid and dry nasal swabs for Abbott ID Now. Regardless of method of collection and sample type, Abbott ID Now COVID-19 had negative results in a third of the samples that tested positive by Cepheid Xpert Xpress when using nasopharyngeal swabs in viral transport media and 45% when using dry nasal swabs.

Basu A ，Zinger T ，Inglima K ，Woo KM ，Atie O ，Yurasits L ，See B ，Aguero-Rosenfeld ME ... -  《-》

Value of swab types and collection time on SARS-COV-2 detection using RT-PCR assay.

Liu M ，Li Q ，Zhou J ，Ai W ，Zheng X ，Zeng J ，Liu Y ，Xiang X ，Guo R ，Li X ，Wu X ，Xu H ，Jiang L ，Zhang H ，Chen J ，Tian L ，Luo J ，Luo C ... -  《-》

Commercial Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Molecular Assays: Superior Analytical Sensitivity of cobas SARS-CoV-2 Relative to NxTAG CoV Extended Panel and ID NOW COVID-19 Test.

We implemented multiple nucleic acid amplification test platforms because of the limited availability of test kits for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the early stages of the pandemic. Interpretation of results generated by different platforms and prioritization for testing algorithms required cross-comparison. To compare the analytical sensitivity of 3 commercial SARS-CoV-2 molecular assays, selected samples were studied in parallel with Cobas SARS-CoV-2 test, NxTAG CoV Extended Panel, and ID NOW COVID-19 assays. A total of 8043 SARS-CoV-2 tests performed from March 22 to April 19, 2020, were included in this study. For all 1794 positive specimens detected by the cobas SARS-CoV-2 assay, the cycle threshold (Ct) values were manually tracked and plotted to demonstrate the distribution of sample viral levels. Additionally, 50 and 63 low-positive specimens (Ct values >32) as well as 50 and 61 consecutive positive specimens by the cobas assay were tested with NxTAG and ID NOW, respectively, to estimate their relative sensitivities. The Ct values of cobas SARS-CoV-2-positive samples were evenly distributed throughout ranges of 13.32 to 39.50 (mean, 25.06) and 13.60 to 42.49 (mean, 26.45) for ORF1 and E gene targets, respectively. NxTAG reliably detected only specimens with E gene Ct values lower than 33, and is estimated to detect 89.4% of positive specimens detected by cobas assay. ID NOW had performance variation independent of Ct value and is estimated to detect 83.5% of cobas positives. Clinical specimens exhibit a wide range of viral burden, with a significant portion at low levels. Analytical sensitivity of testing platforms is critical for reliable detection of SARS-CoV-2 and uniform care to patients.

Jin R ，Pettengill MA ，Hartnett NL ，Auerbach HE ，Peiper SC ，Wang Z ... -  《-》

Comparison of Four Molecular In Vitro Diagnostic Assays for the Detection of SARS-CoV-2 in Nasopharyngeal Specimens.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel human coronavirus that causes coronavirus disease 2019 (COVID-19), was first discovered in December 2019 as the cause of an outbreak of pneumonia in the city of Wuhan, Hubei province, China. The clinical presentation of COVID-19 is fairly nonspecific, and symptoms overlap those of other seasonal respiratory infections concurrently circulating in the population. Furthermore, it is estimated that up to 80% of infected individuals experience mild symptoms or are asymptomatic, confounding efforts to reliably diagnose COVID-19 empirically. To support infection control measures, there is an urgent need for rapid and accurate molecular diagnostics to identify COVID-19-positive patients. In the present study, we evaluated the analytical sensitivity and clinical performance of the following four SARS-CoV-2 molecular diagnostic assays granted emergency use authorization by the FDA using nasopharyngeal swabs from symptomatic patients: the New York SARS-CoV-2 Real-time Reverse Transcriptase (RT)-PCR Diagnostic Panel (modified CDC) assay, the Simplexa COVID-19 Direct (Diasorin Molecular) assay, GenMark ePlex SARS-CoV-2 (GenMark) assay, and the Hologic Panther Fusion SARS-CoV-2 (Hologic) assay. This information is crucial for both laboratories and clinical teams as decisions on which testing platform to implement are made.

Zhen W ，Manji R ，Smith E ，Berry GJ ... -  《-》