Acceptable performance of the Abbott ID NOW among symptomatic individuals with confirmed COVID-19

Abstract

Introduction. The ID NOW is FDA approved for the detection of SARS-CoV-2 in symptomatic individuals within the first 7 days of symptom onset for COVID-19 if tested within 1 h of specimen collection. Gap statement. Clinical data on the performance of the ID NOW are limited, with many studies varying in their study design and/or having small sample size. Aim. In this study we aimed to determine the clinical performance of the ID NOW compared to conventional RT-PCR testing. Methodology. Adults with COVID-19 in the community or hospital were recruited into the study. Paired throat swabs were collected, with one throat swab transported immediately in an empty sterile tube to the laboratory for ID NOW testing, and the other transported in universal transport media and tested by an in-house SARS-CoV-2 RT-PCR assay targeting the E gene. Results. In total, 133 individuals were included in the study; 129 samples were positive on either the ID NOW and/or RT-PCR. Assuming any positive result on either assay represents a true positive, positive per cent agreement (PPA) of the ID NOW compared to RT-PCR with 95 % confidence intervals was 89.1 % (82.0–94.1%) and 91.6 % (85.1–95.9%), respectively. When analysing individuals with symptom duration ≤7 days and who had the ID NOW performed within 1 h (n=62), ID NOW PPA increased to 98.2 %. Conclusion. Results from the ID NOW were reliable, especially when adhering to the manufacturer’s recommendations for testing.

Then and NOW: A Prospective Population-Level Validation of the Abbott ID NOW SARS-CoV-2 Device Implemented in Multiple Settings for Testing Asymptomatic and Symptomatic Individuals

“…While ID NOW testing was mandated to be done within 1 hour from collection, short periods of time from transportation may potentially affect performance. 10 Secondly, a higher proportion of individuals with lower viral loads may be tested in hospitals and via mobile. For mobile testing (mostly outbreaks), individuals with symptoms were possibly early in their symptom onset at time of testing, whereas those presenting to hospitals were possibly late in their symptom onset; both of which can be associated with higher Ct values and, therefore, lower viral loads.…”

Diagnostic accuracy of the Abbott ID NOW SARS-CoV-2 rapid test for the triage of acute medical admissions

“…Such ‘false positives’ may arise because of detection of residual viral RNA following recent infection in individuals who are post-infectious (likely explanation in 5/31), or because a single SARS-CoV-2 PCR is an imperfect reference standard and may itself miss individuals with current infection (likely in 9/31) [ 3 ]. Stokes et al found that on further evaluating nine ID NOW false positives, 5/9 were PCR positive on repeat testing of the same sample using different assays [ 15 ]. Our remaining false positives may represent asymptomatic COVID-19 with a false-negative PCR [ 31 , 32 ] or contamination.…”

“…Results can be integrated automatically with hospital records which saves time and error by avoiding manual recording, and allows easy evaluation and audit. The reported performance of ID NOW in the literature to date has mostly come from small studies across a range of settings, with sensitivities ranging from 55-98% and specificities 95-100% when using RT-PCR as the gold standard [ 8 , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] ]. Sensitivity approaches 100% when PCR results with a cycle threshold (Ct) value >30, suggesting a lower viral load, are excluded [ 15 , [19] , [20] , [21] ].…”

“…The reported performance of ID NOW in the literature to date has mostly come from small studies across a range of settings, with sensitivities ranging from 55-98% and specificities 95-100% when using RT-PCR as the gold standard [ 8 , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] ]. Sensitivity approaches 100% when PCR results with a cycle threshold (Ct) value >30, suggesting a lower viral load, are excluded [ 15 , [19] , [20] , [21] ]. Here we describe the real-world diagnostic performance of ID NOW as a COVID-19 triage tool in the ED of a large acute hospital.…”

Avoiding false positive SARS-CoV-2 rapid antigen test results with point-of-care molecular testing on residual test buffer

“…4 This NAAT-RDT is simple and provides rapid results with high sensitivity and specificity, but its single-specimen processing limits its scalability for testing large populations. [14][15][16] Instead, this NAAT-RDT was evaluated for rapid confirmation of SARS-CoV-2 using RTB from positive Ag-RDTs, at the site of sample collection (Table 1). The assessment was performed in two stages on asymptomatic individuals presenting to urban rapid testing sites.…”