Utility of Ct values in differentiating COVID-19 reinfection versus prolonged viral shedding in an immunocompromised patient

We describe the case of a 26-year-old man who presented to an outside hospital with concerns of blurred vision. He subsequently tested positive for COVID-19 and his lab work suggested acute leukaemia. The patient was admitted to our hospital and completed a course of remdesivir. He eventually tested negative for COVID-19 before initiating chemotherapy. Two days after starting chemotherapy, he developed a neutropenic fever and tested positive for COVID-19. Through this case, we aim to bring attention to patients who recurrently test positive with COVID-19 PCR testing, thereby causing a dilemma of differentiating between reinfections and prolonged shedding of the virus, as well as understand and use cycle threshold values to discern these aetiologies.