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 2^nd scenario (83.27% vs. 55.27%) while the specificity was higher in the 1^st scenario (95% vs. 65%).

Conclusion: 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.