Sensitivity of ID NOW and RT–PCR for detection of SARS-CoV-2 in an ambulatory population

Abstract

Diagnosis of SARS-CoV-2 (COVID-19) requires confirmation by Reverse-Transcription Polymerase Chain Reaction (RT-PCR). Abbott ID NOW provides fast results but has been criticized for low sensitivity. Here we determine the sensitivity of ID NOW in an ambulatory population presenting for testing. The study enrolled 785 symptomatic patients, 21 of whom were positive by both ID NOW and RT-PCR, and 2 only by RT-PCR. All 189 asymptomatic patients tested negative. The positive percent agreement between the ID NOW assay and the RT-PCR assay was 91.3%, and negative percent agreement was 100%. The results from the current study were included into a larger systematic review of literature where at least 20 subjects were simultaneously tested using ID NOW and RT-PCR. The overall sensitivity for ID NOW assay was calculated at 84% (95% CI 55- 96%) and had the highest correlation to RT-PCR at viral loads most likely to be associated with transmissible infections.

Fast and reliable real life data on COVID-19 triaging with ID NOW

“…In conclusion, the real-life results of this study are in line with others [3] suggesting that ID NOW significantly simplified the diagnostic process of COVID-19 triaging of febrile patients admitted to ED during the pandemic. Patients admission was faster with a more accurate triaging.…”

“…ID NOW COVID-19 assay (Abbott Molecular Diagnostics, Des Plaines, IL, USA) has recently proved a simple, rapid, specific and sensitive diagnostic tool for the early detection and identification of SARS-CoV-2 [3] , [4] , [5] , [6] . In addition to clinical laboratories, this assay can be performed by trained non-laboratory personnel in patient care settings such ED.…”

Relative sensitivity of anterior nares and nasopharyngeal swabs for initial detection of SARS-CoV-2 in ambulatory patients: Rapid review and meta-analysis

“…Given that many of the patients in the Callahan study were tested as part of follow-up after laboratory-confirmed diagnosis, it is possible that more rapid reduction of viral loads in the anterior nares than in the nasopharynx with disease progression accounts for the results of these studies, and that heterogeneity in patient populations may account for differences observed in other studies included in this review. Reduced viral loads in asyptomatic vs symptomatic patients could possibly also account for the reduced sensitivity for ANS in the Albany cohort, since Ct values tend to be higher in asymptomatic than symptomatic patients [23], but viral load information was not published for these patients. Examination of Table 1 shows no obvious relationship between the prevalence of disease in the tested populations and the sensitivity of ANS, MTS, or NPS identified in those populations, nor does it suggest a relationship between hospitalization and sensitivity.…”

“…least with some assay systems, ANS may be less effective in subjects with low viral loads than it is in those with higher viral loads, the data that we examined does not provide a robust test of ANS efficacy in the identification of asymptomatic infection. Data in the literature strongly suggests that asymptomatic patients have lower viral loads than symptomatic patients, but also show that many asymptomatic patients are effectively diagnosed using ANS [23].…”

Implementation of the Abbott ID Now COVID-19 assay at a tertiary care center: a prospective pragmatic implementation study during the third wave of SARS-CoV-2 in Ontario

“…The ID Now is intended as a POC diagnostic device, and the ID Now COVID-19 assay allows for rapid isothermal molecular detection of the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) gene in symptomatic patients within 7 days of symptoms onset ( Abbott 2021 ). Previously published evaluations have reported positive percent agreement (PPA) ranging from 48 to 94.9% when compared to laboratory-based RT-PCR testing ( Procop et al, 2021 , Zhen et al, 2020 , Jin et al, 2020 , Lephart et al, 2021 , Harrington et al, 2020 , Serei et al, 2021 , Rhoads et al, 2020 , Smithgall et al, 2020 , Moore et al, 2020 , Lee and Song, 2021 , Mitchell and George, 2020 , Thwe and Ren, 2020 , Basu et al, 2020 , Tu et al, 2021 , Farfour et al, 2021 , Tworek et al, 2021 ). Discrepancies in published performance are likely a result of differences in sample types (anterior nasal or nasopharyngeal swabs), and most studies pre-date the FDA advisory warning on the reduced performance of the assay when swabs are transported in universal or viral transport media ( Office of the Commissioner 2020 ).…”