Correlation and influencing factors analysis of the cycle threshold value in detection of novel coronavirus nucleic acid(Omicron) and the negative conversion cycle in infected patients

Objective: To explore the relationship between the cycle threshold (Ct) value of ORF1ab gene and N gene in the first admission detected by novel coronavirus (Omicron) nucleic acid and the negative conversion cycle of infected patients. Methods: 5 212 patients with novel coronavirus omicron variant infection were admitted to the Northern Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from March 2022 to April 2022 were collected, according to the patient′s previous history and the tests of relevant indexes after admission, including 2 746 cases in non-basic disease group and 2 466 cases in the basic disease group. All subjects received the Ct value of the ORF1ab genes and the N genes tests. Statistical analysis of the difference of the negative conversion cycle of ORF1ab gene and N gene between non-basic disease group and basic disease group under different Ct values at the first admission. Pearson linear correlation analysis was used to assess the association of Ct value of ORF1ab gene and N gene with the negative conversion cycle, and multiple linear regression was used to analyze the factors affecting the negative conversion cycle. Results: The Ct values of ORF1ab gene and N gene in patients novel coronavirus infection were negatively correlated with the negative conversion cycle (rORF1ab=-0.4622, P