The Importance of Cycle Threshold Values in the Evaluation of Patients with Persistent Positive PCR for SARS-CoV-2: Case Study and Brief Review

Abstract

Some patients recover from COVID-19, but their reverse transcription-polymerase chain reaction (RT-PCR) for SARS-CoV-2 remains persistently positive. In the evaluation of these patients, it is important to define the cycle threshold (Ct) value of the RT-PCR test. This article will present a case study, address relevant findings and interpretation of the RT-PCR test, and explain the use of Ct values in defining when a healthcare worker may return to work. Our current approach is to allow health care workers with persistently positive RT-PCR to return to work if the Ct value is greater than 35.