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

Abstract

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<0.01; rN=-0.5428, P<0.01). In the case of Ct value ≤20 and 20 <Ct value ≤30, there was a significant difference in the negative conversion cycle between the group with basic diseases and the group with non-basic disease, which the negative conversion cycle of the group with basic diseases was significantly higher than that of the group with non-basic disease (P<0.05); When the Ct value of the ORF1ab gene increases by one cycle, the negative conversion cycle is shortened by 0.21 days, and when the Ct value of the N gene increases by one cycle, the negative conversion cycle is shortened by 0.26 days, in addition, age and basic diseases are risk factors. Conclusions: The Ct values of ORF1ab gene and N gene in the first admission are related to the negative conversion cycle of patients with novel coronavirus (Omicron) infection, which can be used as an independent predictor of the negative conversion cycle of patients with novel coronavirus infection and have a certain value in guiding patients with novel coronavirus infection to reduce the frequency of nucleic acid detection and to assess disease progression.

Keywords

• |novel coronavirus|orf1ab gene|n gene|cycle threshold value|negative conversion cycle