This study was initiated with the general design to test all COVID-19 symptomatic prospective hospital admissions in the ED with the Abbott ID NOW™ and, if negative, recollect expeditiously and test on a laboratory-based molecular analyzer. The key conceptual elements of this prospective validation study were originally designed by CH senior infectious disease physicians and operationalized by emergency department (ED) and laboratory leadership. Given the proposed use of the Abbott ID NOW™ to test predominantly symptomatic hospital admissions in the context of the uncertainty imparted by these studies, Cottage Health purposely designed a process using dry swabs only with immediate on-site testing to comprehensively ascertain the actual negative test performance of the Abbott ID NOW™.

Our analysis of this false negative discordance was coincident with the published studies from Northwell Health 3 and media reports about Cleveland Clinic 4 highlighting this issue. Our validation with direct smears demonstrated 100% concordance however, there was only 80% concordance with the archived VTM specimens. Although the system can utilize a variety of throat, nasal or nasopharyngeal swabs with specific allowance for storage stability, the Instruction for Use (IFU) 1 states that “optimal test performance” is achieved utilizing the swabs provided with the collection kit and “should be tested as soon as possible after collection.” By mid-April 2020, Cottage Health (CH) adopted the use of the Abbott ID NOW™ analyzer and validated utilizing archived positive and negative specimens in viral transport media (VTM) as well as direct smears from known positive and negative patients. The analyzer uses isothermal nucleic acid amplification of a single unique region of the RNA-dependent RNA polymerase (RdRp) genome using a self-contained, combined collection and testing kit. The Abbott ID NOW™ COVID-19 assay, which received Food and Drug Administration Emergency Use Authorization (FDA EUA) approval on 27 March 2020, is a rapid molecular diagnostic test particularly designed for on-site, rapid turnaround point of care (POC) testing. There was strict adoption of the procedures listed in the Abbott ID NOW™ Instruction for Use (IFU) 1 insert delineating preferred practices for “optimal test performance.” Under these conditions, our institution demonstrated a significant negative percent agreement with 116 out of 117 patients correlating, which equates to a 99.1% concordance similar to a recently reported correlation study2.

A tightly controlled, extended laboratory validation was performed at our medical center to determine the negative test agreement of the Abbott ID NOW™ compared with the BD MAX™ analyzer, a laboratory-based, two target, molecular analyzer with a sensitive cycle threshold (Ct) positive cutoff value of ≤ 42. The capability to provide both rapid disposition and correct patient classification during this COVID-19 pandemic is critically important with broad infection control implications for both patients and healthcare staff. The utilization of rapid diagnostic tests is integral to optimizing workflow within the hospital and/or procedural-based clinics. The Abbott ID NOW™ COVID-19 assay is a rapid molecular diagnostic test particularly designed for on-site, rapid turnaround point of care (POC) testing.

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