INTRODUCTION: Without universal access to point-of-care SARS-CoV-2 testing, many hospitals rely on clinical judgement alone for identifying cases of COVID-19 early .
METHODS: Cambridge University Hospitals NHS Foundation Trust introduced a 'traffic light' clinical judgement aid to the COVID-19 admissions unit in mid-March 2020 . Ability to accurately predict COVID-19 was audited retrospectively across different stages of the epidemic .
RESULTS: One SARS-CoV-2 PCR positive patient (1/41 , 2 %) was misallocated to a 'green' (non-COVID-19) area during the first period of observation, and no patients (0/32 , 0 %) were mislabelled 'green' during the second period . 33 of 62 (53 %) labelled 'red' (high risk) tested SARS-CoV-2 PCR positive during the first period, while 5 of 22 (23 %) 'red' patients were PCR positive in the second .
CONCLUSION: COVID-19 clinical risk stratification on initial assessment effectively identifies non-COVID-19 patients. However, diagnosing COVID-19 is challenging and risk of overcalling COVID-19 should be recognised, especially when background prevalence is low.