The diagnostic accuracy of the ID NOW COVID-19 point of care test in acute hospital admissions

Background

Prompt identification of patients with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection on admission to hospital is crucial to ensuring initiation of appropriate treatment, optimising infection control and maintaining patient flow. The Abbott ID NOW™ COVID-19 assay (ID NOW) is a point-of-care, isothermal nucleic acid amplification test, capable of producing a result within minutes, potentially placing it as an invaluable tool in helping to control the coronavirus-disease 2019 (COVID-19) pandemic.

Objectives

To evaluate the diagnostic accuracy of ID NOW in acute hospital admissions.

Study design

A prospective approach to data collection was undertaken in consecutive patients with ID NOW and Hologic Aptima™ SARS-CoV-2 transcription-mediated amplification assay (Aptima TMA) results, across three hospitals in the south-west of England between 1st March and 30th September 2021. A nasal swab was taken for ID NOW and a combined nose and throat swab for Aptima TMA. Measures of diagnostic accuracy were calculated for ID NOW against Aptima TMA. This study was conducted during a period of alpha and delta strain predominance.

Results

19,698 ID NOW assays were performed, of which 12,821 had an Aptima TMA assay performed within 24 hours. ID NOW had sensitivity of 85.2 % (95 % CI, 82.2–87.9) and specificity of 99.6 % (95 % CI, 99.4–99.7) compared with the reference assay. The overall PPV was 91.0 % (95 % CI, 88.5–93.0) and the overall NPV was 99.3 % (95 % CI, 99.1–99.4).

Conclusions

ID NOW offers a valid diagnostic tool to detect SARS-CoV-2, performing comparably to a reference laboratory-based assay which takes longer to provide results.