Background: The role of laboratory parameters and the relationship of them with radiology reports, CT scan and clinical outcomes in screening of COVID-19 patients not been definitely established, but this disease presented a major challenge in the field of clinical tests, radiology reports, clinical outcomes that help to monitoring and treatment COVID-19 disease. Methods: This study was performed on 340 suspected COVID-19 patients, who presented to Chamran Hospital, Shiraz University of Medical Sciences Shiraz, Iran from 20 February to 31 August, 2020. Information each patient’s will be completed using a data collection forms based on records. The evaluation of lungs involvement in CT scan and their relationship with laboratory indicator including biochemical and hematological factors, is the best scale for the severity and prognosis of Covid 19 patients. Results and Conclusion: The findings of this study indicated ALT, AST, CRP, NEU, LDH, and Urea have very good accuracy in predicting cases with positive RT-PCR for COVID-19, respectively. In this study we shown the correlation of clinical and laboratory findings with CT-based quantitative score of pulmonary involvement in COVID-19 pneumonia and attempted that our findings could be usable to development future clinical research associated with COVID-19 infection and show the relationship of reports CT scan and clinical outcomes in the diagnosis and severity of patients with COVID-19.