Comparative study of four SARS-CoV-2 Nucleic Acid Amplification Test (NAAT) platforms demonstrates that ID NOW performance is impaired substantially by patient and specimen type

Paul R Lephart; Michael A Bachman; William LeBar; Scott McClellan; Karen Barron; Lee Schroeder; Duane W Newton

doi:10.1016/j.diagmicrobio.2020.115200

Comparative study of four SARS-CoV-2 Nucleic Acid Amplification Test (NAAT) platforms demonstrates that ID NOW performance is impaired substantially by patient and specimen type

Diagn Microbiol Infect Dis. 2021 Jan;99(1):115200. doi: 10.1016/j.diagmicrobio.2020.115200. Epub 2020 Sep 3.

Authors

Paul R Lephart¹, Michael A Bachman², William LeBar², Scott McClellan², Karen Barron², Lee Schroeder², Duane W Newton²

Affiliations

¹ Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA. Electronic address: plephart@umich.edu.
² Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA.

Abstract

The COVID-19 pandemic in the United States created a unique situation where multiple molecular SARS-CoV-2 diagnostic assays rapidly received Emergency Use Authorization by the FDA and were validated by laboratories and utilized clinically, all within a period of a few weeks. We compared the performance of four of these assays that were evaluated for use at our institution: Abbott RealTime m2000 SARS-CoV-2 Assay, DiaSorin Simplexa COVID-19 Direct, Cepheid Xpert Xpress SARS-CoV-2, and Abbott ID NOW COVID-19. Nasopharyngeal and nasal specimens were collected from 88 ED and hospital-admitted patients and tested by the four methods in parallel to compare performance. ID NOW performance stood out as significantly worse than the other 3 assays despite demonstrating comparable analytic sensitivity. Further study determined that the use of a nasal swab compared to a nylon flocked nasopharyngeal swab, as well as use in a population chronically vs. acutely positive for SARS-CoV-2, were substantial factors.

Keywords: COVID-19; Ct value; Molecular diagnostics; Nasal swab; Nasopharyngeal swab; SARS-CoV-2.

Publication types

Comparative Study

MeSH terms

COVID-19 / diagnosis*
COVID-19 Nucleic Acid Testing / methods*
COVID-19 Nucleic Acid Testing / standards
Emergency Service, Hospital
Hospitals, University
Humans
Inpatients
Limit of Detection
Nasopharynx / virology
Nose / virology
SARS-CoV-2 / genetics
SARS-CoV-2 / isolation & purification*
Sensitivity and Specificity
United States / epidemiology