COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

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Diagnosis Bianco G, Boattini M, Barbui AM, et al. Evaluation of an antigen-based test for hospital point-of-care diagnosis of SARS-CoV-2 infection. J Clin Virol. 2021 Jun;139:104838. doi: 10.1016/j.jcv.2021.104838. Epub 2021 Apr 21.

BACKGROUND: An accurate diagnosis is essential to identify and manage SARS-CoV-2 infected patients and implement infection control measures. Although real-time reverse transcription polymerase chain reaction (RT-PCR) is the current recommended laboratory method, several rapid antigen point-of-care tests (POCTs) were developed as frontline testing for SARS-CoV-2 infection diagnosis.

OBJECTIVES: The aim of this study was to assess a recently CE-approved POCT, SARS-CoV-2 Ag Test on the LumiraDx™ Platform (LumiraDx GmbH, Cologne, Germany) for the identification of SARS-COV-2 infected subjects at hospital setting.

METHODS: LumiraDx POCT was implemented in three hospital settings: adult and pediatric emergency departments and occupational medicine department along two-month period during the second peak of Italian SARS-CoV-2 pandemic. Rapid antigen testing was performed on direct nasal swabs and results were compared with those obtained by Xpert Xpress SARS-CoV-2 assay.

RESULTS: Overall sensitivity, specificity, NPV and PPV were 90.3%, 92.1%, 95.1%, and 84.9%, respectively, compared to reference method. Sensitivity, specificity, PPV and NPV for symptomatic group were 89.3% [95% IC 84.2-93.3], 88.2% [95% IC 72.5-96.7], 97.8% [95% IC 94.6-99.1], and 58.8% [95% IC 48.4-68.5], respectively. Sensitivity, specificity, PPV and NPV for asymptomatic group were 92.1% [95% IC 85-96.5], 92.3% [95% IC 89.9-94.4], 67.9% [95% IC 61.3-73.8], and 98.5% [95% IC 97.1-99.2], respectively. False positive and negative antigen testing results in both symptomatic and asymptomatic group were observed.

CONCLUSION: SARS-CoV-2 Ag POCT may represent an interesting tool to rapidly identify symptomatic or asymptomatic infected subjects. However, in hospital setting in which false negative or false positive results may have relevant implications, confirmatory NAAT always remains necessary for the appropriate management of patients.

Discipline / Specialty Area Score
Emergency Medicine
Hospital Doctor/Hospitalists
Internal Medicine
Pediatric Emergency Medicine
Comments from MORE raters

Emergency Medicine rater

We have been using a rapid test for screening emergency surgical cases on admission to our hospital and we also always do a confirmatory PCR. We have been surprised by a few rapid-neg and pcr-positive cases. This study (even if with a different test kit) confirms our local approach.

Emergency Medicine rater

Study done on a relevant fact.