One-step and sequential SARSCOV-2 polymerase chain reaction tests would not work every time.

INTRODUCTION: RT-PCR is widely used as a diagnostic test for the detection of SARS-CoV-2. In this study, we aim to describe the clinical utility of serial PCR testing in the final detection of COVID-19. METHOD: We collected multiple nasopharyngeal swab samples from patients who had negative RT-PCR test on the first day after hospitalization. RT-PCR tests were performed on the second day for all patients with initial negative result. For the patients with secondary negative results on day 2, tertiary RT-PCR tests were performed on day 3 after hospitalization. RESULT: Among 68 patients with initial negative test results, at the end of follow-up, the mortality number was 20 (29.4%). About 33.8% of patients had subsequent positive PCR test results for the second time and 17.4% of the patients who performed third PCR test had positive result. CONCLUSION: Based on this study, serial RT-PCR testing is unlikely to yield additional information.

COVID-19 with repeated positive test results for SARS-CoV-2 by PCR and then negative test results twice during intensive care: a case report.

BACKGROUND: Determining the infectiousness of patients with coronavirus disease 2019 is crucial for patient management. Medical staff usually refer to the results of reverse transcription polymerase chain reaction tests in conjunction with clinical symptoms and computed tomographic images. CASE PRESENTATION: We report a case of a 62-year-old Japanese man who twice had positive and negative test results by polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 over 48 days of hospitalization, including in intensive care. His respiratory symptoms and computed tomographic imaging findings consistent with coronavirus disease 2019 improved following initial intensive care, and the result of his polymerase chain reaction test became negative 3 days before discharge from the intensive care unit. However, 4 days after this first negative result, his polymerase chain reaction test result was positive again, and another 4 days later, he had a negative result once more. Eight days after the second polymerase chain reaction negative test result, the patient's test result again became positive. Finally, his polymerase chain reaction results were negative 43 days after his first hospitalization. CONCLUSIONS: This case emphasizes the importance of repeat polymerase chain reaction testing and diagnosis based on multiple criteria, including clinical symptoms and computed tomographic imaging findings. Clinical staff should consider that a negative result by polymerase chain reaction does not necessarily certify complete coronavirus disease 2019 recovery.