Comparison between the accuracy of chest computerized tomography vs. reverse transcriptase polymerase chain reaction in a tertiary care center in Lebanon; along with their correlation to mortality, morbidity and symptoms in COVID-19 patients

OBJECTIVES: Chest Computerized Tomography has been widely used in COVID patients' assessment. Hence the question arises as to whether there is any correlation between the Ct value and findings on Chest CT scan or clinical presentation of the patient. We wanted to test the hypothesis of whether low Ct values (≤30) in RT-PCR were associated with a high mortality rate, CT scan findings, or with comorbidities such as immunosuppression and lung disease. METHODS: The radiographic records and RT-PCR Ct values of 371 COVID patents diagnosed at the American University of Beirut Medical Center were reviewed. RESULTS: We found out that the sensitivity of chest CT scan compared to RT-PCR, the gold standard, turned out to be 74% (95% CI 69–79%). Specificity, on the other hand was 33% (95% CI 16–55%). The positive predictive value of CT was 94% (95% CI 91–97%) and the negative predictive value was 8% (95% CI 4–16%). low Ct values in RT-PCR were not associated with a higher mortality rate (p-value = 0.416). There was no significant positive association between low Ct value and suspicious CT scan findings (typical and indeterminate for COVID-19), with a p-value of 0.078. There was also no significant association between low Ct value and immunosuppression (p-value = 0.511), or lung disease (p-value =0.06). CT scan findings whether suspicious or not for COVID-19 infection, were not shown to be significantly associated with respiratory symptoms of any kind. No association was found between a history of lung disease, immunosuppression and suspicious CT scan findings for COVID-19. CONCLUSION: As long as this pandemic exists, nucleic acid testing was and remains the gold standard of COVID-19 diagnosis worldwide and in our community as it has a superior diagnostic accuracy to CT scan and higher sensitivity (94% vs 74%).