Cherian, Sree S.

Rhoads, Daniel D.

Sadri, Navid

Schmotzer, Christine L.

Stempak, Lisa M.

English

Scholarly Commons@CWRU

Case Western Reserve University Scholarly Commons @ Case Western Reserve University Faculty Scholarship All Scholarship Collections 7-23-2020 Comparison of Abbott ID Now, DiaSorin Simplexa, and CDC FDA Emergency Use Authorization Methods for the Detection of SARS-CoV-2 from Nasopharyngeal and Nasal Swabs from individuals Diagnosed with COVID-19 Daniel D. Rhoads Case Western Reserve University, ddr26@case.edu Sree S. Cherian Case Western Reserve University, ssc120@case.edu Lisa M. Stempak Case Western Reserve University, lms180@case.edu Christine L. Schmotzer Case Western Reserve University, clh2@case.edu Navid Sadri Case Western Reserve University, nxs460@case.edu Author(s) ORCID Identifier: Daniel D. Rhoads Navid Sadri Follow this a d additional works at: https:// ommons.case.edu/facultyworks  Part of the COVID-19 Commons Recommended Citation Rhoads DD, Cherian SS, Roman K, Stempak LM, Schmotzer CL, Sadri N. 2020. Comparison of Abbott ID Now, DiaSorin Simplexa, and CDC FDA emergency use authorization methods for the detection of SARS-CoV-2 from nasopharyngeal and nasal swabs from individuals diagnosed with COVID19. J Clin Microbiol 58:e00760-20. https://doi .org/10.1128/JCM.00760-20. This Letter to the Editor is brought to you for free and open access by the All Scholarship Collections at Scholarly Commons @ Case Western Reserve University. It has been accepted for inclusion in Faculty Scholarship by an authorized administrator of Scholarly Commons @ Case Western Reserve University. For more information, please contact digitalcommons@case.edu. CWRU authors have made this work freely available. Please tell us how this access has benefited or impacted you! Comparison of Abbott ID Now, DiaSorin Simplexa, and CDCFDA Emergency Use Authorization Methods for the Detectionof SARS-CoV-2 from Nasopharyngeal and Nasal Swabs fromIndividuals Diagnosed with COVID-19Daniel D. Rhoads,a,b Sree S. Cherian,a,b Katharine Roman,a Lisa M. Stempak,a,b Christine L. Schmotzer,a,b Navid Sadria,baDepartment of Pathology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USAbDepartment of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USAKEYWORDS COVID-19, nucleic acid amplification, SARS-CoV-2, coronavirus,emergency use authorization, in vitro diagnostic, virologyDozens of in vitro diagnostics (IVDs) have received emergency use authorization(EUA) from the U.S. Food and Drug Administration (FDA) for the detection ofsevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but how well theseassays perform using clinical specimens has hardly been studied. This study comparedthe positive percent agreement (PPA) of ID Now (Abbott, Chicago, IL, USA) andSimplexa (DiaSorin, Saluggia, Italy) using a modified CDC method as the referencestandard (1). All three methods are used as part of standard of care testing within ourhospital system. Ninety-six remnant clinical specimens from April 2020 that testedpositive for SARS-CoV-2 using standard of care testing were selected based on conve-nience and retested using the three methods. Fourteen negative controls (universaltransport medium [UTM]) were included to control for carryover contamination. Spec-imens included 11 supervised self-collected nasal swabs in 2 ml normal saline and85 provider-collected nasopharyngeal swabs in 3 ml UTM. The online Medcalc tool(https://www.medcalc.org/calc/diagnostic_test.php) was used to determine the exactClopper-Pearson 95% confidence intervals (95% CI). It is well documented that IVDs forSARS-CoV-2 can return false-negative results in individuals with coronavirus disease2019 (COVID-19) (2), and our study did not attempt to determine the clinical sensitivityof these assays.The instructions for use (IFU) were followed for all methods with the exception thatnasal swabs in saline were included, but these specimens are not explicitly describedas acceptable in all of the assays’ IFU. Other deviations from the IFU for the CDC methodinclude the following: (i) using 7500 Fast instead of 7500 Fast Dx instrument, (ii) usingan alternate RNA extraction method (Maxwell RSC instrument with viral TNA kit [catalogno. AS1330; Promega, Madison, WI, USA]), and (iii) interpreting “inconclusive” (onepositive target) results as “detected.”The results are shown in Table 1. The modified CDC assay detected SARS-CoV-2 inall 96 specimens (range of threshold cycle [CT] values, 11.1 to 39.6). The ID Now assaydetected SARS-CoV-2 in 90 of 96 specimens (PPA, 94% [95% CI, 87 to 98%]). TheSimplexa assay detected SARS-CoV-2 in 92 of 96 specimens (PPA, 96% [95% CI, 90 to99%]) (range of CT values, 9.3 to 34.5).The modified CDC assay detected both N1 and N2 targets in 94 of 96 specimens. Inthe other two specimens, the modified CDC assay detected only one of its two targetsat 39 CT, and SARS-CoV-2 was not detected using ID Now and Simplexa in these twospecimens. In six other specimens, SARS-CoV-2 was not detected by only one of theCitation Rhoads DD, Cherian SS, Roman K,Stempak LM, Schmotzer CL, Sadri N. 2020.Comparison of Abbott ID Now, DiaSorinSimplexa, and CDC FDA emergency useauthorization methods for the detection ofSARS-CoV-2 from nasopharyngeal and nasalswabs from individuals diagnosed with COVID-19. J Clin Microbiol 58:e00760-20. https://doi.org/10.1128/JCM.00760-20.Editor Alexander J. McAdam, BostonChildren’s HospitalCopyright © 2020 Rhoads et al. This is anopen-access article distributed under the termsof the Creative Commons Attribution 4.0International license.Address correspondence to Daniel D. Rhoads,ddr26@case.edu.Accepted manuscript posted online 17April 2020PublishedLETTER TO THE EDITORcrossmAugust 2020 Volume 58 Issue 8 e00760-20 jcm.asm.org 1Journal of Clinical Microbiology23 July 2020assays; both targets in the modified CDC assay were detected at 32 CT in these sixspecimens. Strong correlation of CT values was observed when plotting the modifiedCDC assay N1 and N2 targets against the Simplexa S and Orf1ab targets (R2  0.89 to0.91).In summary, the 95% CIs for the PPA were overlapping for the ID Now and Simplexaassays when using the modified CDC method as the reference standard. The samplesize of this study was not large enough to conclude that one of these assays had clearlysuperior or inferior performance for the detection of SARS-CoV-2 from upper respiratoryspecimens in liquid transport medium. In addition to an assay’s limit of detection andsensitivity, considerations of other important variables such as turnaround time, com-plexity, cost, workflow, specimen type and stability, and availability of supplies, re-agents, and equipment may influence selection of a health system’s standard of careIVD that is implemented to detect SARS-CoV-2 RNA.ACKNOWLEDGMENTNo outside funding was used to support this investigation.REFERENCES1. Biswas B. 2016. Clinical performance evaluation of molecular diagnostictests. J Mol Diagn 18:803– 812. https://doi.org/10.1016/j.jmoldx.2016.06.008.2. Fang Y, Zhang H, Xie J, Lin M, Ying L, Pang P, Ji W. 19 February 2020.Sensitivity of chest CT for COVID-19: comparison to RT-PCR. Radiologyhttps://doi.org/10.1148/radiol.2020200432.TABLE 1 Positive percent agreement (PPA) of the Abbott ID Now and DiaSorin Simplexaassays for the detection of SARS-CoV-2 was determined using a modified CDC assay asthe reference standardAssayNo. of specimensPPA (%) (95% CI)SARS-CoV-2 detected SARS-CoV-2 not detectedAbbott ID Now 90 6 94 (8798)DiaSorin Simplexa 92 4 96 (9099)Modified CDC assay 96 0 Not applicableLetter to the Editor Journal of Clinical MicrobiologyAugust 2020 Volume 58 Issue 8 e00760-20 jcm.asm.org 2

Comparison of Abbott ID Now, DiaSorin Simplexa, and CDC FDA Emergency Use Authorization Methods for the Detection of SARS-CoV-2 from Nasopharyngeal and Nasal Swabs from individuals Diagnosed with COVID-19

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Comparison of Abbott ID Now, DiaSorin Simplexa, and CDC FDA Emergency Use Authorization Methods for the Detection of SARS-CoV-2 from Nasopharyngeal and Nasal Swabs from individuals Diagnosed with COVID-19

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