Diagnostic performance and inter-observer variability of CO-RADS in the triage of patients with suspected COVID-19 infection: initial experience in Zagazig University Hospital

Purpose
In many healthcare settings in developing nations, multislice computed tomography (MSCT) imaging may be the only available diagnostic modality for patients with suspected COVID-19 infection, due to a shortage of laboratory kits. This study aimed to evaluate the diagnostic performance and interobserver variability of CO-RADS (COVID-19 Reporting and Data System) in the triage of patients with suspected COVID-19 infection in Zagazig University Hospital.

Material and methods
This study included 2500 patients with suspected COVID-19 infection, mean age 60.61 years ± 13.89. 61.4% were male. Unstable patients requiring urgent invasive ventilation, acute coronary syndrome patients, pregnant females, and patients with RT-PCR results available prior to MSCT were excluded from this study. RT-PCR was performed in all patients included in the study.

Results
Fever and dry cough were the most common clinical symptoms, detected in 80.16% and 52.00%, respectively. The most common comorbidities were cardiovascular diseases, followed by chronic lung disease and diabetes, found in 27.36%, 22.80%, and 18.00%, respectively. Of the 1500 RT-PCR-positive patients, 40% had CO-RADS score 5, while 3.4% had CO-RADS score 1. Of the 1000 RT-PCR-negative patients, 36% had CO-RADS score 2 and 1% were scored as CO-RADS 5. There was excellent agreement in the studied patients as the weighted κ value was 0.846, which was more pronounced at CO-RADS 5 (24.40%). The sensitivity of CO-RADS was higher in the 2nd scenario (83.27% vs. 55.27%) while the specificity was higher in the 1st scenario (95% vs. 65%).

Conclusions
The CO-RADS scoring system is a sensitive and specific method that can help in the diagnosis of COVID-19 during the peak of the COVID-19 pandemic. CO-RADS is a triage test in resource-constrained environments, assisting in the optimization of RT-PCR tests, isolation beds, and intensive care units.