Clinical Performance of RT-PCR and Chest CT Scan for Covid-19 Diagnosis; A Systematic Review

 Due to their availability and rapid turnaround time, the supplemental role of chest computed tomography (CT) scan and real-time polymerase chain reaction (RT-PCR) is growing for early diagnosis of patients with COVID-19. However, due to the low efficiency of viral nucleic acid detection as well as low specificity of chest CT scan for detecting COVID-19 pneumonia, both methods show incomplete clinical performance for proper COVID-19 disease diagnosis. The purpose of this review was to compare the clinical performance of two methods and to evaluate the diagnostic values of chest CT scan and RT-PCR for suspected COVID-19 patients.

We systemically searched PubMed, Cochrane, from December 2019 to the end of April 2020. Clinical research papers in goal fields that reviewed COVID-19 patients, whom chest CT scan, and PCR testing were performed together were included. 

In total, we found 536 studies; and finally168 studies were shortlisted. Following title and abstract screening, we reached 83 studies based on the inclusion and exclusion criteria. Conducted screen by the full text covered 28 studies, which led to data extraction. By the full-text assessment of 28 included studies, we found 4486 assessed patients. Totally, 3164 patients had positive chest CT scans, and 3014 patients had positive PCR results. The finding showed that recent studies on the diagnostic performance of RT-PCR and chest CT scan have commonly been reported from China. 

The results from this review indicate that the chest CT scan should be used for symptomatic and hospitalized patients. Moreover, chest CT scan should not be used as a primary screening tool for diagnosing COVID-19. Application of RT-PCR as the first line diagnosis is still recommended.