A chest-CT and clinical chemistry based flowchart for rapid COVID-19 triage at emergency departments - a multicenter study

Kurstjens, S.; Göttgens, E.-L.; Smit, B.; Postma, B.; Kluge, C.; van der Horst, A.; Lamboo, E. H. J.; Janssen - Te Slaa, C. M. M.; Herpers, R.; Kluiters-de Hingh, Y. C. M.; du Mee, A.; Veuger, M.; van Marum, R.; de Jager, P.; Elisen, M. G. L. M.; Kusters, R.; Schuijt, M.; Thelen, M. H. M.

Background Due to the large number of patients with coronavirus disease 19 (COVID-19), rapid diagnosis at the emergency department (ED) is of critical importance. In this study we have developed a flowchart based on two well-known diagnostic methods: the 'corona-score' and the 'CO-RADS'. This flowchart can be used in hospitals that use chest-CT, instead of chest X-ray, for COVID-19 suspected patients at the ED. Methods ED patients (n=1904) from the Jeroen Bosch Hospital, Amphia Hospital, HagaHospital, Elisabeth TweeSteden Hospital, Bernhoven Hospital and Slingeland Hospital were included. A laboratory-based 'corona-score', without radiology, called the 'lab-corona-score' was combined with a chest-CT based radiology scoring system (CO-RADS), to develop a flowchart. The performance was assessed by sensitivity/specificity analyses using the RT-PCR outcome or the physician's final diagnosis as golden standard. Results Out of the 1904 patients, 611 (32.1%) patients tested positive for the SARS-CoV-2 virus. The lab-corona-score alone had an AUC of 0.86, a sensitivity of 87% and a specificity of 88% using cut-off values of 0-2 (negative) and 8-10 (positive). Of 255 patients, from the Amphia and Slingeland Hospitals, a CO-RADS score was determined. The flowchart, which combined the 'CO-RADS' with the 'lab-corona-score', was developed based on data from Slingeland Hospital (sensitivity 97%, specificity 96%). Hereafter, the performance of the flowchart was validated using an independent dataset from Amphia hospital, and reached a sensitivity of 98% and specificity of 93%. A decision could be made in 79% of the patients, which was correct in 95% of the cases. Conclusion This flowchart, based on radiology (CO-RADS) and clinical chemistry parameters (lab-corona-score), results in a rapid and accurate diagnosis of COVID-19 at the ED.