The Clinical Utility of Serial Procalcitonin and Procalcitonin Clearance in Predicting the Outcome of COVID-19 Patients

Background: The pandemic of coronavirus disease 2019 (COVID-19) represents a great threat to global health. Sensitive tests that effectively predict the disease outcome are essentially required to guide proper intervention. Objectives: To evaluate the prognostic ability of serial procalcitonin (PCT) measurement to predict the outcome of COVID-19 patients, using PCT clearance (PCT-c) as a tool to reflect its dynamic changes. Methods: A prospective observational study of inpatients diagnosed with COVID-19 at the Quarantine Hospitals of Ain-Shams University, Cairo, Egypt. During the first five days of hospitalization, serial PCT and PCT-c values were obtained and compared between survivors and non-survivors. Patients were followed up to hospital discharge or in-hospital mortality. Results: Compared to survivors, serial PCT levels of non-survivors were significantly higher (p<0.001) and progressively increased during follow-up, in contrast, PCT-c values were significantly lower (p<0.01) and progressively decreased. Receiver operating characteristic (ROC) curve analysis showed that by using the initial PCT value alone, at a cut off value of 0.80 ng/ml, the area under the curve for predicting in-hospital mortality was 0.81 with 61.1% sensitivity and 87.3% accuracy. Serial measurements showed better predictive performance and the combined prediction value was better than the single prediction by the initial PCT. Conclusions: Serial PCT measurement could be a useful laboratory tool to predict the prognosis and outcome of COVID-19 patients. Moreover, PCT-c could be a reliable tool to assess PCT progressive kinetics.