CRP and COVID-19: Interestingly, several studies propose the use of CRP and PCT in combination with other inflammatory markers and clinical scores.40,51,54 When using a clinical pulmonary infection score with a PCT cut-off of 0.5 ug/L in severely ill COVID-19 patients, Sathitakorn et al64 reported those with a negative score were less likely to have inappropriate antibiotics used, less likely to have inappropriate empirical antibiotic initiated, and more likely to have antibiotics discontinued at 72 hours.