SARS CoV2 RT-PCR cycle threshold (Ct) values and the risk of developing acute respiratory distress syndrome in patients with Covid19

ABSTRACT

Background. SARS-CoV-2 viral loads may aid in the risk stratification of patients with COVID-19. Methods. 486 patients tested positive for SARS Cov2 by real time RT-PCR were included in this study. All the tests were performed on nasopharyngeal swabs during the first week after symptom onset using Sansure Biotech™ SARS Cov2 real time RT-PCR kits. Patient's condition was monitored over a period of one month after the onset of symptoms. Results. The mean Ct value in the group of patients who developed acute respiratory distress syndrome (ARDS +) was 18.27 (95% CI 17.43-19.10) while for the ARDS group it was 33.06 (95% CI 32.77-33.34). Discussion. The Ct values in the group of patients who developed ARDS (ARDS +) were significantly lower than those observed in the ARDS- group. By setting a cut-off value, the determination Ct values (on a qualitative technique) from nasopharyngeal swabs performed during the first week after symptom onset will assist clinicians in risk-stratifying patients. Conclusion. Our data show that the determination of SARS CoV2 RTPCR cycle threshold values from nasopharyngeal swabs performed during the first week after symptom onset may aid in the risk stratification of patients with COVID-19