Screening COVID 19 with Chest CT in Preference to RT PCR: Based on Mortality Analysis

Corona Virus Disease 2019 (COVID-19) became the outbreak of infectious diseases emergency worldwide. It remains unknown whether the RT-PCR test results was associated with the prognosis of COVID-19 patients or not. In this study, a total number of 495 patients with typical chest CT feature and symptom consistent with COVID-19 were retrospectively included from Jan 23, 2020 to Feb 26, 2020. 186 (37.58%), 32 (6.46%) and 277 (55.96%) COVID-19 patients had initial positive, suspected and negative RT-PCR results, respectively. The mean age was 58.55 years and 254(51.3%) were older than 60 years. 60.00% (297/495), 22.02% (109/495) and 17.98% (89/495) of COVID-19 patients were common, severe and critically type, respectively. There were no significant differences of age, gender, time from onset to hospitalization and severity classification in the patients with initial positive and negative RT-PCR result. The mortality rate of patients with positive and negative were 7.14% and 7.94%. Patients with initial negative or initial positive RT-PCR results had no significant difference of mortality rate (c2=4.079, p=0.130). The number of patients with lymphocyte ratios under the normal level was significantly larger in patients with initial negative RT-PCR results (59/92) compared with the patients with initial positive result (86/167), p=0.033. COVID-19 patients with positive or negative RT-PCR results had no significant difference in severity and mortality. Chest CT may be a more effective tool to screen COVID-19 in preference to RT-PCR.