Acceptable Performance of the Abbott ID NOW Among Symptomatic Individuals with Confirmed COVID-19

Abstract

INTRODUCTIONPoint of care diagnostic tests for SARS-CoV-2, such as the ID NOW, have great potential to help combat the COVID-19 pandemic. The ID NOW is approved by the United States Food and Drug Administration (FDA) 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 hour of specimen collection. However, clinical data on the performance of the ID NOW is limited, with many studies deviating from the manufacturer’s instructions and/or having small sample size.METHODSAdults 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. Positive percent agreement (PPA) was calculated.RESULTS133 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, 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 analyzing individuals with symptoms ≤ 7 days and who had the ID NOW performed within an hour, ID NOW PPA increased to 98.2%.DISCUSSIONIn this study, SARS-CoV-2 results from the ID NOW were reliable, especially when testing was adhered to manufacturer’s recommendations.

Tools and Techniques for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)/COVID-19 Detection

“…The assay has processing times as low as 5 min for positive results with high viral loads and 15 min for specimens with lower viral loads or negative results. Compared to LDTs or commercial NAATs, many recent studies have demonstrated an excellent specificity/negative percent agreement (NPA) near 100% but relatively poor sensitivity/positive percent agreement (PPA) of between 48% and 70% for the detection of SARS-CoV-2, while other studies showed a high specificity/NPA (∼100%) as well as high sensitivity/PPA values above 90% ( 290 , 301 , 341 – 347 ).…”

“…The reasons for the disparities in sensitivity/PPA between studies are likely multifold and include differences in the patient population (setting, host factors, and the presence or not of compatible symptoms), the specimen type, the timing between collection and testing, the transport conditions used (dry swabs or transport media), the quality of specimens (prospective versus retrospective), the spectrum of viral loads in the specimens evaluated (proportion of specimens with low viral loads), or differences in performance characteristics of the comparator method(s) ( 290 , 301 , 341 – 347 ). For example, the swab type affected IDNCOV performance, where NP swabs showed a PPA of 64%, compared to 48% with nasal swabs ( 348 ).…”

“…When specimens were categorized by C T values, both INDCOV and Xpert showed 100% PPA for specimens with medium to high viral loads ( C T values of <30), but at low viral loads ( C T values of >30), the PPA for IDNCOV was 34.3%, versus 97.1% for Xpert ( 290 ). In a recent study, Stokes et al compared IDNCOV to an LDT and showed an excellent PPA of 89.1% (95% CI, 82.0% to 94.1%) for IDNCOV ( 347 ). Notably, the PPA increased to 98.2% by following the manufacturer’s recommendations for testing under EUA for symptomatic individuals tested ≤7 days after symptom onset and within an hour of collection using the appropriate swab ( 347 ).…”

“…In a recent study, Stokes et al compared IDNCOV to an LDT and showed an excellent PPA of 89.1% (95% CI, 82.0% to 94.1%) for IDNCOV ( 347 ). Notably, the PPA increased to 98.2% by following the manufacturer’s recommendations for testing under EUA for symptomatic individuals tested ≤7 days after symptom onset and within an hour of collection using the appropriate swab ( 347 ). Overall, these studies not only demonstrate that the performance characteristics of a test are dependent on numerous factors but also reflect the need for validations or verification of these factors in the settings and conditions where NAAT-based RDTs are applied ( 274 , 288 ).…”

Molecular point-of-care testing for SARS-CoV-2 using the ID NOW™ System in Emergency Department: Prospective Evaluation and Implementation in the Care Process

“…Patients aged 14-100 (median age 63) recruited into the study were included irrespective of the reason for referral to the emergency department but showed symptoms associated with COVID-19 and / or a high epidemiological risk (Table 1) [3,13]. The evaluation of the collected findings within the scope of the study was carried out with the consent of the patients and completely anonymised.…”