COVID-19 Reporting System, CT Severity Score Are Effective Diagnostic Tools

Doctor Showing Digital Tablet To Patient in ICU
Doctor Showing Digital Tablet To Patient in ICU
The COVID-19 Reporting and Data System (CO-RADS) in combination with a CT severity score are easy to use diagnostic tools to guide clinicians in diagnosing COVID-19.

Among patients who present to the emergency department (ED) with moderate to severe symptoms indicative of possible coronavirus disease 2019 (COVID-19) infection, the COVID-19 Reporting and Data System (CO-RADS) and the corresponding computed tomography severity score (CTSS) are easy to use tools designed to assist radiologists and guide clinicians in diagnosing the disease, according to study results published in CHEST.

A prospective, observational study was conducted in 2 tertiary centers in The Netherlands between March 19 and May 28, 2020. Investigators sought to prospectively validate the use of CO-RADS as a COVID-19 diagnostic tool in the ED to compare CT data across different countries and settings. The researchers also evaluated whether the corresponding CTSS was linked to disease prognosis. Both the CO-RADS and the CTSS were introduced by the Radiological Society of The Netherlands, in an effort to compare data across a variety of settings in a systematic and reproducible manner by analyzing and reporting the results.

The current study included a total of 741 consecutive adult patients with suspected COVID-19 who received a chest CT and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) test. A CO-RADS score of at least 4 was the optimal cutoff for discriminating between a positive and a negative PCR, with an area under the curve of 0.91 (95% CI, 0.89-0.94), a sensitivity of 89.4% (95% CI, 84.7-93.0), a specificity of 87.2% (95% CI, 83.9-89.9), a negative predictive value of 94.6% (95% CI, 92.4-96.2), and a positive predictive value of 76.4% (95% CI, 71.9-80.3).

A total of 25 patients had false-negative CT scans (CO-RADS ≤3, but a positive PCR). Patients with a CO-RADS score of 2 or less had a significantly shorter duration of symptoms compared with those with a CO-RADS score of more than 2. Overall, 44% of these patients had a symptom duration of fewer than 3 days, 72% were admitted, 28% received oxygen, and 8% required treatment in the intensive care unit (ICU).

A significant association was observed between CTSS and hospital admission, ICU admission, and 30-day mortality, with adjusted odds ratios per point increase in CTSS of 1.19 (95% CI, 1.09-1.28), 1.23 (95% CI, 1.15-1.32), and 1.14 (95% CI, 1.07-1.22), respectively. The intraclass correlation coefficients for CO-RADS and CTSS were 0.94 (95% CI, 0.91- 0.96) and 0.82 (95% CI, 0.70-0.90), respectively.

Study limitations included the use of a high-prevalence study setting and potential reduced generalizability because of the use of additional chest imaging.

The investigators concluded that the findings support the use of CO-RADS and CTSS in triage, diagnosis, and management decisions for patients who present to the ED with suspected COVID-19. Additional research in other countries and care settings is warranted in order to enhance the robustness of the current results.


Lieveld AWE, Azijli K, Teunissen BP, et al. Chest CT in COVID-19 at the ED: validation of the COVID-19 reporting and data system (CO-RADS) and CT severity score. CHEST. Published online November 30, 2020. doi:10.1016/j.chest.2020.11.026