CO RADS grade of HRCT Thorax and RT PCR testing for the diagnosis of coronavirus disease 2019 (COVID 19): A descriptive hospital based study of asymptomatic planned surgery cases.

Background: The coronavirus disease 2019 (COVID-19) reporting and data system (CO-RADS) grade of high-resolution computed tomography (HRCT)-thorax scan investigation is an innovative tool for the diagnosis of COVID-19 patients. By this tool, majority of moderate-to-severe COVID-19 patients are screened to detect lung pathologies. Hardly any study has explored its use vis-a-vis reverse transcriptase-polymerase chain reaction (RT-PCR) in asymptomatic patients.

Objectives: (1) The objective of the study is to assess the frequency COVID-19 patients among asymptomatic subjects who were admitted in the hospital for planned surgery, (2) estimate the sensitivity and specificity of CO-RADS grade of HRCT-thorax investigation for the diagnosis of COVID-19 patients where RT-PCR test was considered as "Gold Standard" test.

Methodology: A descriptive retrospective study was conducted by studying the records in the case files of 150 patients who were admitted in the Department of General Surgery, Man Mohini Health Clinic, Murshidabad, West Bengal for minor surgical procedures between September 1 and December 31, 2020. Data were collected from hospital records. The CO-RADS grade of HRCT-thorax investigation and RT-PCR test were performed for the diagnosis of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) virus. The MS-excel application was applied for data analysis.

Results: The mean age of the participants was 42.58 ± 14.29 years. A total of 17 (11%) and 39 (26%) of the patients were diagnosed with COVID-19 by HRCT-thorax and RT-PCR test, respectively. The sensitivity and specificity of CO-RADS grade of HRCT-thorax investigation for diagnosis of COVID-19 patients were 43.58% and 100%, respectively. The positive and negative predictive values of CO-RADS grade of HRCT-thorax investigation were 100% and 83.45%, respectively.

Conclusions: The frequency of asymptomatic patients with COVID-19 that was missed by HRCT thorax was high, compared to the gold standard RT-PCR, reflecting its low sensitivity and low negative predictive value in the diagnosis of SARS-CoV-2 virus infection. Hence, it is difficult to conclude in favor of HRCT thorax as first-line screening modality in all individuals.