COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

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Diagnosis James AE, Gulley T, Kothari A, et al. Performance of the BinaxNOW COVID-19 Antigen Card test relative to the SARS-CoV-2 real-time reverse transcriptase polymerase chain reaction assay among symptomatic and asymptomatic healthcare employees. Infect Control Hosp Epidemiol. 2021 Jan 25:1-15. doi: 10.1017/ice.2021.20.
Abstract

The sensitivity of the BinaxNOW coronavirus disease 2019 (COVID-19) Ag Card test (BinaxNOW) was 51.6% among asymptomatic healthcare employees relative to real-time reverse transcriptase polymerase chain reaction (rRT-PCR). The odds of a positive BinaxNOW test decreased as cycle threshold value increased. BinaxNOW could facilitate rapid detection and isolation of asymptomatically infected persons in some settings while rRT-PCR results are pending.

Ratings
Discipline / Specialty Area Score
Occupational and Environmental Health
Emergency Medicine
Infectious Disease
Intensivist/Critical Care
Hospital Doctor/Hospitalists
Internal Medicine
Comments from MORE raters

Emergency Medicine rater

Having a test that can quickly identify some patients with Covid would be useful in managing the flow in EDs.

Intensivist/Critical Care rater

This is a single centre study aimed to evaluate the performance of the BinaxNOW (rapid test) for detecting asymptomatic SARS-CoV-2 positive persons in relation with traditional RT-PCR test. Results showed a specificity of 97%. However regarding sensitivity, the rates were 83% for symptomatic and 51% for asymptomatic patients. Although the test is reliable to identify actual covid-19 positive symptomatic patients early, there is no benefit to its application for screening asymptomatic individuals.

Intensivist/Critical Care rater

This is valuable information. The test being slightly more than 50% accurate is disappointing and seems marginally better than a coin toss. It is surprising to see the authors suggest that this test may be used as a screening tool. Clinical evaluation may be significantly better.

Occupational and Environmental Health rater

Antigenic tests have a known reduced sensitivity as compared to RT-PCR for SARS-CoV-2. Their utility rests with a result much faster than RT-PCR, suitable for point-of-care use.