@article {de Roos00737-2020, author = {Marlise P. de Roos and Iris D. Kilsdonk and Pieter-Paul W. Hekking and Jan Peringa and Nynke G. Dijkstra and Peter W.A. Kunst and Paul Bresser and Herre J. Reesink}, title = {Chest computed tomography and alveolar{\textendash}arterial oxygen gradient as rapid tools to diagnose and triage mildly symptomatic COVID-19 pneumonia patients}, volume = {7}, number = {1}, elocation-id = {00737-2020}, year = {2021}, doi = {10.1183/23120541.00737-2020}, publisher = {European Respiratory Society}, abstract = {Background In the coronavirus disease 2019 (COVID-19) pandemic, rapid clinical triage is crucial to determine which patients need hospitalisation. We hypothesised that chest computed tomography (CT) and alveolar-arterial oxygen tension ratio (A-a) gradient may be useful to triage these patients, since they reflect the severity of the pneumonia-associated ventilation/perfusion abnormalities.Methods A retrospective analysis was performed in 235 consecutive patients suspected for COVID-19. The diagnostic protocol included low-dose chest CT and arterial blood gas analysis. In patients with CT-based COVID-19 pneumonia, the association between {\textquotedblleft}need for hospitalisation{\textquotedblright} and A-a gradient was investigated by a multivariable logistic regression model. The A-a gradient was tested as a predictor for need for hospitalisation using receiver operating characteristic curve analysis and a logistic regression model.Results 72 out of 235 patients (mean{\textpm}sd age 55.5{\textpm}14.6 years, 40\% female) screened by chest CT showed evidence for COVID-19 pneumonia. In these patients, A-a gradient was shown to be a predictor of need for hospitalisation, with an optimal decision level (cut-off) of 36.4 mmHg (95\% CI 0.70{\textendash}0.91, p\<0.001). The A-a gradient was shown to be independently associated with need for hospitalisation (OR 1.97 (95\% CI 1.23{\textendash}3.15), p=0.005; A-a gradient per 10 points) from CT severity score (OR 1.13 (95\% CI 0.94{\textendash}1.36), p=0.191), National Early Warning Score (OR 1.19 (95\% CI 0.91{\textendash}1.57), p=0.321) or peripheral oxygen saturation (OR 0.88 (95\% CI 0.68{\textendash}1.14), p=0.345).Conclusion Low-dose chest CT and the A-a gradient may serve as rapid and accurate tools to diagnose COVID-19 pneumonia and to select mildly symptomatic patients in need for hospitalisation.Low-dose chest CT and alveolar{\textendash}arterial oxygen gradient appear to be rapid and accurate tools to diagnose $\#$COVID19 pneumonia, and to select mildly symptomatic patients in need of hospitalisation https://bit.ly/2N3rJlE}, URL = {https://openres.ersjournals.com/content/7/1/00737-2020}, eprint = {https://openres.ersjournals.com/content/7/1/00737-2020.full.pdf}, journal = {ERJ Open Research} }