The clinical symptoms, blood laboratory data, O2 saturation and high resolution computed tomography (HRCT) findings are critical factors in diagnosis of COVID-19 infection. In this study, 105 hospitalized patients suspected of having COVID-19 were evaluated. Finally, the data of 83 confirmed cases by HRCT and RT-PCR were analyzed. 61.40% of the patients had a comorbidity disease. 89.20% had fever, 92.00% cough, 91.40% dyspnea. Abnormal CRP seen in 77.80% of the patients following by 66.70% lymphopenia, and 60.30% neutrophilia. Also, ALP (abnormal vs. normal) and score of HRCT assessment variables had a significant effect on the positiveness of HRCT findings. 87.95% had abnormal HRCT with 41% bilateral multilobar patchy ground glass opacity (GGO). Moreover, there was a statistically significant association between level of O2 saturation and HRCT results. Our findings showed that male patients with middle age and comorbidity disease were more susceptible to the COVID-19 infection. Additionally, clinical features, blood laboratory findings, O2 saturation and HRCT findings are critical factors in prognosis of COVID-19 infection.