Comparative Evaluation of Cartridge-Based Abbott ID NOW Test With Probe-Based Real-Time Reverse Transcription Polymerase Chain Reaction Assay for Detection of SARS-CoV-2

Abstract

Background: The gold standard test for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recommended by WHO is real-time reverse transcription polymerase chain reaction (RT-PCR), which has a turnaround time of five to six hours. Abbott ID NOW (Abbott Diagnostics Scarborough, Inc., Scarborough, ME, USA), the cartridge-based loop-mediated isothermal amplification (LAMP) assay, was approved by FDA for Emergency Use Authorization as rapid point of care testing. The present study was planned to evaluate the performance of the cartridge-based Abbott ID NOW test by comparing it to the currently used standard probe-based real-time RT-PCR method for detection of SARS-CoV-2.Methodology: A cross-sectional study was conducted in a tertiary care hospital in the eastern part of India after getting institutional ethics committee (IEC) approval. Two hundred fifty-nine cases of various age groups of both sexes who were advised for testing for SARS-CoV-2 were included in the study. Nasopharyngeal swabs were collected according to protocol advisory by the Indian Council of Medical Research (ICMR), India. Dry swabs were sent for Abbott ID NOW testing and swabs in viral transport medium were sent for probe-based RT-PCR assay using the CoviPath kit (Thermo Fisher Scientific, Bangalore, India). The data were collected and statistical analysis was performed using Statistical Package for Social Sciences (SPSS) (IBM Corp., Armonk, NY, USA). Sensitivity, specificity, positive and negative predictive values for ID NOW were calculated taking RT-PCR as the gold standard.Results: Out of 259 patients enrolled in the study, 49% were symptomatic for coronavirus disease 2019 . The prevalence rate of SARS-CoV-2 was 20.84% among the study population. Sensitivity and specificity, positive and negative predictive values of ID NOW test in comparison to RT-PCR assay was found to be 87%, 98%, 92.1% and 96.8% respectively. ID NOW detected seven out of 54 (12.9%) cases as false negative who were found to be positive with RT-PCR, with mean Ct value of the target genes >34.Conclusions: In this study the overall sensitivity for ID NOW assay was found to be lower, but specificity, positive and negative predictive values were found to be higher. It had the highest correlation to RT-PCR among symptomatic patients and at higher viral loads. Due to the ease of use and shortest result time for detecting COVID-19, ID NOW test could be used as a point-of-care test. But for all tests, the results should be interpreted according to the clinical and epidemiological context.

Correlation of Breakthrough Infection During the Omicron Wave With Seropositivity of Vaccinated Patients Undergoing Hemodialysis

“…Molecular detection of SARS-CoV-2 RNA by RT-PCR was carried out using the Taqman probe-based method as described earlier [ 15 ]. In brief, a nasopharyngeal sample (NPS) was collected for the detection of SARS-CoV-2 by RT-PCR.…”

“…The ribonuclease (RNase) P target was used as an internal control in the reaction. A Ct value of <37 for the target gene was considered positive for SARS-CoV-2 [ 15 ]. SARS-CoV-2 RNA detection by RT-PCR performed on >11 or more days after completion of both doses of vaccination was considered a breakthrough infection [ 16 , 17 ].…”

Clinical evaluation of DIAGNOVIR SARS-CoV-2 ultra-rapid antigen test performance compared to PCR-based testing

“…ECDC has accepted the minimal criteria with a performance closer to RT-PCR, which is ≥ 90% sensitivity and > 98% specificity, as also recommended by EU Health Security Committee (HSC) 15 . Since the beginning of the pandemic, RT-PCR has routinely been used and remained the gold standard to confirm the diagnosis [16][17][18] . However, the clinical sensitivity of the RT-PCR can decrease up to 40% [19][20][21] .…”

Direct comparison of Altona-SARS-CoV-2 dual target RT-qPCR Assay with commercial LAMP Assay using throat washes in health care staff testing

“…Nevertheless, the likelyhood ratios and the diagnostic odds ratio open the possibility to use the colorimetric LAMP assay in settings like rural laboratories with limited equipment and qPCR capacities or in situations with a need of high test coverage due to high numbers of expected positively cases, because sensitivity and specificity of the LAMP assay are for sure higher than that of many rapid antigen tests [7] , [8] , [9] , [10] and are in the same range as for the Abbott ID Now IVD real time LAMP assay [11] , [12] . Thereby, it would be worth to test if the assay sensitivity may be improved by automatic read out systems.…”