Assessing Role of HRCT Screening Policy among COVID-19 Test-Negative Symptomatic Patients in Ahmedabad, India

Introduction: To effectively contain the disease and controlling the progression of the COVID19 pandemic, Ahmedabad Municipal Corporation (AMC) implemented a unique policy to screen symptomatic individuals with negative diagnostic tests using the High-Resolution Computed Tomography (HRCT) scan. Objective: To analyse the findings of the HRCT screening policy during the COVID19 pandemic situation. Method: During the period of HRCT Screening policy, i.e., 23 July 2020 to 31 December 2020, a total of 41034 scan record from 25 CT scan centers were available. A retrospective analysis of these secondary data available with the health department of AMC was carried out after due permission from the local authority. Results: A total of 11337 [27.63%, 95% Confidence Interval (CI) 27.20-28.06] were reported as COVID positive. Males reported higher positivity (27.87%) than females (27.17%), however the difference was statistically not significant (Z=1.512, p=0.131). Age wise positivity shows increasing trend, while zone wise comparison shows positivity in line with the cases from respective zone. Analysis of CT severity score shows that 66.15% had Mild, 26.07% had moderate and 7.78% had severe lung involvement. Conclusion :HRCT screening policy identified additional cases of COVID19 and helped in isolation/admission of a large number of suspected cases which helped immensely in better control of the pandemic. HRCT, when used in combination with other diagnostic tests, plays a crucial role in controlling the pandemic situation