Diagnosis of the Coronavirus disease (COVID-19): rRT-PCR or CT?

Abstract

Purpose: To evaluate the diagnostic value of computed tomography (CT) and real-time reverse-transcriptase-polymerase chain reaction (rRT-PCR) for COVID-19 pneumonia.

Methods: This retrospective study included all patients with COVID-19 pneumonia suspicion, who were examined by both CT and rRT-PCR at initial presentation. The sensitivities of both tests were then compared. For patients with a final confirmed diagnosis, clinical and laboratory data, in addition to CT imaging findings were evaluated.

Results: A total of 36 patients were finally diagnosed with COVID-19 pneumonia. Thirty-five patients had abnormal CT findings at presentation, whereas one patient had a normal CT. Using rRT-PCR, 30 patients were tested positive, with 6 cases initially missed. Amongst these 6 patients, 3 became positive in the second rRT-PCR assay(after 2 days, 2 days and 3 days respectively), and the other 3 became positive only in the third round of rRT-PCR tests(after 5 days, 6 days and 8 days respectively). At presentation, CT sensitivity was therefore 97.2%, whereas the sensitivity of initial rRT-PCR was only 83.3%.

Conclusion: rRT-PCR may produce initial false negative results. We suggest that patients with typical CT findings but negative rRT-PCR results should be isolated, and rRT-PCR should be repeated to avoid misdiagnosis.

Keywords: Coronavirus; Pneumonia; Severe Acute Respiratory Syndrome; Tomography; X-Ray Computed.

Fig. 1

Flowchart for patient inclusion.

Fig. 2

A 45-year-old male patient with COVID-19 pneumonia showed patchy consolidations and ground glass opacities in both lungs. These were mainly distributed peripherally, with a random distribution pattern.

Fig. 3

A 41-year-old female patient presented with a fever for 3 days. CT examination showed ground glass opacities in the upper lobe of right lung (A). rRT-PCR results on the same day were negative. Re-examinations with CT 2 days later showed that CT abnormalities had expanded and increased (B). Second round rRT-PCR remained negative. Upon another repeat rRT-PCR the next day, the patient was confirmed as virus positive.