Diagnostic accuracy of the Abbott ID NOW SARS-CoV-2 rapid test for the triage of acute medical admissions

Journal article

Background: Decisions to isolate patients at risk of having coronavirus disease 2019 (COVID-19) in the emergency department (ED) must be rapid and accurate to ensure prompt treatment and maintain patient flow whilst minimising nosocomial spread. Reverse transcription polymerase chain reaction (RT-PCR) assays are too slow to achieve this, and near-patient testing is being used increasingly to facilitate triage. The ID NOW severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) assay is an isothermal nucleic acid amplification near-patient test which targets the RNA-dependent RNA-polymerase gene. Aim: To assess the diagnostic performance of ID NOW as a COVID-19 triage tool for medical admissions from the ED of a large acute hospital. Methods: All adult acute medical admissions from the ED between 31st March and 31st July 2021 with valid ID NOW and RT-PCR results were included. The diagnostic accuracy of ID NOW [sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV)] was calculated against the laboratory reference standard. Discrepant results were explored further using cycle threshold values and clinical data. Findings: Two percent (124/6050) of medical admissions were SARS-CoV-2 positive on RT-PCR. Compared with PCR, ID NOW had sensitivity and specificity of 83.1% [95% confidence interval (CI) 75.4–88.7] and 99.5% (95% CI 99.3–99.6), respectively. PPV and NPV were 76.9% (95% CI 69.0–83.2) and 99.6% (95% CI 99.5–99.8), respectively. The median time from arrival in the ED to ID NOW result was 59 min. Conclusion: ID NOW provides a rapid and reliable adjunct for the safe triage of patients with COVID-19, and can work effectively when integrated into an ED triage algorithm

Authors: Barnacle, JR; Houston, H; Baltas, I; Takata, J; Kavallieros, K

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Journal of Hospital Infection
• Volume: 123
• Pages: 92-99
• Publication date: 2022-02-23
• DOI: 10.1016/j.jhin.2022.02.010
• EISSN: 1532-2939
• ISSN: 0195-6701
• Language: English
• Keywords: Coronavirus disease 2019 (COVID-19); Confidence interval; Medicine; Emergency medicine; Internal medicine; Emergency department; Infectious disease (medical specialty); Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); Triage; Medical record; Nucleic Acid Amplification Tests; Virology; Disease