%O © Author(s) (or their
employer(s)) 2021. Re-use
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%J BMJ Open
%A H Houston
%A G Deas
%A S Naik
%A K Shah
%A S Patel
%A MG Dottori
%A M Tay
%A SA Filson
%A J Biggin-Lamming
%A J Ross
%A N Vaughan
%A N Vaid
%A GG Rao
%A AK Amin
%A A Gupta-Wright
%A L John
%L discovery10133522
%I BMJ PUBLISHING GROUP
%X Objective: To evaluate a triage algorithm used to identify and isolate patients with suspected COVID-19 among medical patients needing admission to hospital using simple clinical criteria and the FebriDx assay.

Design:: Retrospective observational cohort.

Setting Large acute National Health Service hospital in London, UK.

Participants: All medical admissions from the emergency department between 10 August 2020 and 4 November 2020 with a valid SARS-CoV-2 RT-PCR result.

Interventions: Medical admissions were triaged as likely, possible or unlikely COVID-19 based on clinical criteria. Patients triaged as possible COVID-19 underwent FebriDx lateral flow assay on capillary blood, and those positive for myxovirus resistance protein A (a host response protein) were managed as likely COVID-19.

Primary outcome measures: Diagnostic accuracy (sensitivity, specificity and predictive values) of the algorithm and the FebriDx assay using SARS-CoV-2 RT-PCR from nasopharyngeal swabs as the reference standard.

Results: 4.0% (136) of 3443 medical admissions had RT-PCR confirmed COVID-19. Prevalence of COVID-19 was 46% (80/175) in those triaged as likely, 4.1% (50/1225) in possible and 0.3% (6/2033) in unlikely COVID-19. Using a SARS-CoV-2 RT-PCR reference standard, clinical triage had sensitivity of 96% (95% CI 91% to 98%) and specificity of 61.5% (95% CI 59.8% to 63.1%), while the triage algorithm including FebriDx had sensitivity of 93% (95% CI 87% to 96%) and specificity of 86.4% (95% CI 85.2% to 87.5%). While 2033 patients were deemed not to require isolation using clinical criteria alone, the addition of FebriDx to clinical triage allowed a further 826 patients to be released from isolation, reducing the need for isolation rooms by 9.5 per day, 95% CI 8.9 to 10.2. Ten patients missed by the algorithm had mild or asymptomatic COVID-19.

Conclusions: A triage algorithm including the FebriDx assay had good sensitivity and was useful to ‘rule-out’ COVID-19 among medical admissions to hospital.
%K Science & Technology, Life Sciences & Biomedicine, Medicine, General & Internal, General & Internal Medicine, COVID-19, molecular diagnostics, infection control
%N 8
%T Utility of the FebriDx point-of-care assay in supporting a triage algorithm for medical admissions with possible COVID-19: an observational cohort study
%D 2021
%V 11