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

Problem The utility of the polymerase chain reaction (PCR) cycle threshold (C-t) 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) C-t 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 C-t values available. While C-t values from ORF1ab and S genes were highly correlated for a given specimen, there was no correlation between C-t 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 C-t values between survivors and non-survivors or mild/moderate versus severe/critical illness at the maximum point of illness. Conclusion SARS-CoV-2 C-t values have limited value in the management of COVID-19.