Background: Patients admitted to hospital with COVID-19 must be rapidly identified and isolated to prevent nosocomial transmission . However, isolation facilities are often limited, and SARS-CoV-2 RT-PCR results are too slow to inform emergency department triage . We evaluated a pragmatic triage algorithm to isolate patients with suspected COVID-19 using simple clinical criteria and the FebriDx assay .
Methods: All medical admissions in a large UK hospital 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 who tested MxA positive were isolated . We evaluated the accuracy of the algorithm and the FebriDx assay compared to SARS-CoV-2 RT-PCR from nasopharyngeal swabs as the reference standard .
Results: Between 10th August 2020 and 4th November 2020 , 136/3,443 medical admissions (4.0 %) were diagnosed with RT-PCR confirmed COVID-19 . Prevalence of COVID-19 was 45.7% (80/175) in those triaged as likely , 4.1% (50/1,225) in possible and 6/2,033 (0.3 %) in unlikely COVID-19 . Compared to SARS-CoV-2 RT-PCR, clinical triage had sensitivity of 95.6% (130/136) and specificity of 61.5% (2027/3297), whilst the triage algorithm including FebriDx had sensitivity of 92.6% (126/136) and specificity of 86.4% (2849/3297). The triage algorithm reduced the need for 2,859 patients to be admitted to isolation rooms . The patients missed by the algorithm had mild or asymptomatic COVID-19 .
Conclusions: A simple triage algorithm including FebriDx assay had good sensitivity and is a useful rule-out for COVID-19 . The algorithm is useful for managing medical admissions from the emergency department.