Chest computed tomography and COVID-19 RT-PCR: The tale of two diagnostic tests in a resource-limited setting

Abstract

Herein, we aimed to report the association between coronavirus disease 2019 (COVID-19) real-time polymerase chain reaction (RT-PCR) and computerized chest tomography (CT), along with hospitalization and mortality in rural secondary care, resource-limited hospital setting, without the capabilities to conduct RT-PCR or report chest CT results in-house. We included patients admitted to the COVID-19 outpatient clinic between August 2020 and January 2021. COVID-19 RT-PCR was the standard for diagnosis. Chest CT scans were categorized into negative, suspicious, or positive rather than using the COVID-19 Reporting and Data System (CO-RADS) system; and pneumonia was classified into mild, moderate, and severe, rather than using the global CT involvement score (CTIS), as provided by outsourcing. Of 954 outpatients admitted, 382 (40%) were RT-PCR positive, and 472 (49.5%) had pneumonia on chest CT. The sensitivity of the chest CT scans for RT-PCR positivity was 62.04%, and specificity was 58.92%. Cohen’s kappa between the RT-PCR and chest CT results showed fair agreement (K=0.205, p=0.0001). Hospitalization and death rates were higher in the RT-PCR positive patient population (p=0.001 and 0.0001). In cases with negative CT scans for pneumonia, the death rates were higher in the RT-PCR positive population (p=0.025, chi-square test). RT-PCR and chest CT had a fair agreement, and the sensitivity and specificity of chest CT scans for RT-PCR positivity were low. Death rates were higher in RT-PCR positive, initial chest CTs negative patients, which underlines the importance of obtaining RT-PCR results in a resource-limited setting to identify patients with a higher risk for mortality.