Lack of correlation between the SARS-CoV-2 cycle threshold (Ct) value and clinical outcomes in patients with COVID-19

Abstract

Problem: The utility of the polymerase chain reaction (PCR) cycle threshold (Ct) values in the management of patients with coronavirus disease 2019 (COVID-19) remains controversial. Methods: We assessed the correlation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Ct values in nasopharyngeal swab samples with the oxygen requirements at the time of sample collection. Specimens were tested with the Simplexa PCR platform, which targets the SARS-CoV-2 ORF1ab and S genes. Results: We identified 23 COVID-19 patients with 49 Ct values available. While Ct values from ORF1ab and S genes were highly correlated for a given specimen, there was no correlation between Ct values for any of these target genes and the oxygen requirements of the patient at the time of sample collection. We found no differences in the initial nor the nadir Ct values between survivors and non-survivors or mild/moderate versus severe/critical illness at the maximum point of illness. Conclusion: SARS-CoV-2 Ct values have limited value in the management of COVID-19.