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
Bibliographic record
Abstract
ABSTRACT IMPORTANCE Since December, 2020, the ID NOW was implemented for use in 4 different populations across Alberta: in mobile units as part of community outbreak response, COVID-19 community collection sites, emergency shelters and addiction treatment facilities (ES), and hospitals. OBJECTIVE Diagnostic evaluation of the ID NOW in various real world settings among symptomatic and asymptomatic individuals DESIGN Depending on the implemented site, the ID NOW was tested on patients with symptoms suggestive of COVID-19, asymptomatic close contacts or asymptomatic individuals as part of outbreak point prevalence screening. From Jan – April, a select number of sites also switched from using oropharyngeal swabs to combined oropharyngeal + nasal (O+N) swabs. For every individual tested, two swabs were collected: one for ID NOW testing and the other for either reverse-transcriptase polymerase chain reaction (RT-PCR) confirmation of negative ID NOW results or for variant testing of positive ID NOW results. RESULTS A total of 129,112 paired samples were analyzed (16,061 RT-PCR positive). 81,697 samples were from 42 COVID-19 community collection sites, 16,924 from 69 rural hospitals, 1,927 from 9 ES, 23,802 samples from 6 mobile units that responded to 356 community outbreaks, and 4,762 from 3 community collection sites and 1 ES using O+N swabs for ID NOW testing. ID NOW sensitivity was highest among symptomatic individuals presenting to community collection sites [92.5%, 95% confidence interval (CI) 92.0-93.0%, n=10,633 RT-PCR positive] and lowest for asymptomatic individuals associated with community outbreaks (73.9%, 95% CI 69.8-77.7%, n=494 RT-PCR positive). Specificity was greater than 99% in all populations tested, but positive predictive value (PPV) was lower among asymptomatic populations (82.4–91.3%) compared to symptomatic populations (96.0-96.9%). There was no statistically significant differences in sensitivity with respect to age, gender, NP vs OP swab for RT-PCR confirmation, variants of concern, or with combined oropharyngeal and nasal swabs using COVID-19 ID NOW testing. CONCLUSIONS Sensitivity of ID NOW SARS-CoV-2 testing is highest when used on symptomatic community populations not seeking medical care. Sensitivity and PPV drops by approximately 10% when tested on asymptomatic populations. Using combined oropharyngeal and nasal swabs did not improve ID NOW performance.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".