Efficacy of Abbott ID NOW COVID-19 Using Fresh Nasopharyngeal Specimens Acquired with a Fine Swab

Backgrounds: : Many reported rates of positive results by nicking enzyme amplification reaction (NEAR) applied together with the Abbott ID NOW™ COVID-19 (AIN) test and dry patient samples is lower than rates provided by other nucleic acid amplification tests. Few studies have used fresh samples, however. Methods: We conducted this retrospective study using fresh samples to determine the correlations among fever, associated symptoms, and the NEAR detection rate. Quarantined cases of suspected SARS-CoV-2 infection at Kunimoto ENT clinic (Jan 14, 2022–May 7, 2023) who had been in close contact with SARS-CoV-2-infected individuals were enrolled. Specimens were collected by the thin-diameter nasal sterile swab from the nasopharynx and examined immediately. We evaluated the positive-result rates, fever, and symptoms. Results: The total number of close-contact patients evaluated was 661 and AIN-positive cases was 427. The detection rate in the fever ≥37.4°C patients was 97% (257/266), significantly higher than the corresponding rate in the <37.4°C patients (170/395) (p<0.00001). The detection rate in the patients with ≤1 symptoms other than fever was 98% (394/402). Conclusions: These results suggest that the AIN results are sufficiently dependable when fresh samples are obtained from patients with a fever ≥37.4°C, and with more than one symptom.