key: cord-0932968-qec35qr3
authors: Tworek, Joseph A; Khan, Faisal; Sekedat, Matthew D; Scheidel, Caleb; Malani, Anurag N
title: The utility of rapid nucleic acid amplification testing to triage symptomatic patients and to screen asymptomatic pre-procedure patients for SARS-CoV-2
date: 2020-12-17
journal: Open Forum Infect Dis
DOI: 10.1093/ofid/ofaa607
sha: ac3d9bed93a02bcb5c9db51bb6f02bccb2acfbdf
doc_id: 932968
cord_uid: qec35qr3

We investigate the utility of the ID Now when compared to RT-PCR to triage patients suspected of having COVID-19 presenting to emergency rooms (ERs) and to screen asymptomatic patients presenting for pre-procedural testing. We find it useful when prevalence of COVID-19 is high in symptomatic patents and potentially useful in asymptomatic patients who are likely to be retested if symptoms emerge.

M a n u s c r i p t Dear Editor, Recent studies have cast doubt on the sensitivity and utility of the Abbott ID Now instrument to detect SARS-CoV-2 when compared to conventional RT-PCR [1] [2] [3] [4] [5] . However, finding a role for rapid testing platforms, such as the ID Now, would help to reduce demands on RT-PCR assays. We investigated the utility of the ID Now when compared to RT-PCR to triage patients suspected of having COVID-19 presenting to emergency rooms (ERs) and its utility to screen asymptomatic patients presenting for pre-procedural testing.

For the symptomatic population, we studied 1,569 patients suspected of having COVID-19 across five community teaching hospital ERs from April 15 through April 25, 2020 in southeast Michigan. For the asymptomatic population, we studied 386 patients scheduled for elective surgical procedures between April 15 to May 15, 2020. All asymptomatic patients passed a symptom screening questionnaire at the time of collection, typically two days before the procedure.

In both populations, a foam nasal swab (NS) was collected for testing by the ID Now and a sequential nasopharyngeal swab (NPS) was also collected immediately after collection of the NS. The NPS was sent for conventional RT-PCR if the ID Now results were negative in the symptomatic ER patient population. The NPS was always sent for RT-PCR in the asymptomatic population from preprocedural screening, as this was the local practice standard for several weeks. Internal validation studies of the ID Now prior to its clinical use In symptomatic patients, the overall positive rate was 17.58%, and the overall false negative rate (FNR) was 12.42% (Table 1 ). The FNR decreased as the prevalence of COVID-19 increased for hospitals with significant volume (sites 1-3). The performance agreement (Fleiss Kappa value) shows strong agreement (> 0.80) among sites. In asymptomatic patients, the positive rate was 0.78% by RT-PCR; all 3 patients who were positive by RT-PCR had negative results by ID Now. One patient in retrospect was thought to have symptoms which were not captured by the symptom screen questionnaire.

In the symptomatic group, we examined RT-PCR cycle threshold (Ct) data for the 35 available samples that were positive on the Abbott m2000 and negative for the ID Now. Similar to other studies, Ct values in false negative cases on the ID Now tended to be higher than in those tested positive by RT-PCR alone. [1] [2] [3] [4] [5] Despite the lower sensitivity of the ID Now, its utility depends on the prevalence of COVID-19 and the target population. ID Now proved to be useful to triage rapidly symptomatic patients presenting to ERs, particularly when prevalence was high. Patients with a positive ID Now test were considered to have COVID-19, and were admitted to a COVID-19 unit if hospitalized. Patients with negative ID Now tests were either discharged with instructions to self-quarantine until confirmatory RT-PCR results were available, or hospitalized with the possibility of being located on a COVID-19 unit if RT-PCR results were positive. In asymptomatic patients, the ID Now may be useful in screening for SARS-CoV-2, despite missing 3 of 383 patients. In this population, its usefulness may be increased by directing testing to patients likely to return for repeat testing, either the ID Now or RT-PCR, if symptoms of COVID-19 develop.

The supply chain for COVID-19 testing is strained given surging demand. Shortages have affected the availability of antigen tests, Abbott ID Now and consumables for RT-PCR such as pipette tips, swabs, reagents, and viral transport media leading to prolonged TAT 6 . The more available testing options through innovative approaches for pre-procedure screening and testing symptomatic hospital admissions with rapid testing such as the ID Now will optimize testing capacity.

A c c e p t e d M a n u s c r i p t

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

Clinical evaluation of three sample-toanswer platforms for the detection of SARS-CoV-2

Evaluation of the COVID 19 ID NOW EUA assay

Comparison of Abbott ID Now and Abbott m2000 methods for the detection of SARS-CoV-2 from nasopharyngeal and nasal swabs from symptomatic patients

Comparison of Cepheid Xpert Xpress and Abbott ID Now to Roche cobas for the rapid detection of SARS-CoV-2

COVID-19: Overcoming supply shortages for diagnostic testing

A c c e p t e d M a n u s c r i p t