The role of acute phase proteins for predicting SARS-CoV-2 positivity upon emergency department admission

Background: due to the important abnormalities observed in the concentration of many inflammation/infection biomarkers in patients with coronavirus disease 2019 (COVID-19), this study was aimed to evaluate whether the assessment of C-Reactive Protein (CRP), interleukin 6 (IL-6) and procalcitonin (PCT) could help predicting SARS-CoV-2 positivity at emergency department (ED) presentation in patients with suspected infection. Methods: the study population consisted of patients consecutively admitted to the ED of the University Hospital of Verona, with clinical suspicion of SARS-CoV-2 infection over a 2-week period. Blood samples as well as oropharyngeal and nasopharyngeal swabs were collected upon ED admission. Results: the final study population consisted of 92 patients, 48 with negative and 44 with positive SARS-CoV-2 swabs. No significant differences were observed in concentrations of CRP, IL-6, or PCT between patients with or without acute SARS-CoV-2 infection. A significant correlation was found between CRP and IL-6 in both negative (r=0.77) and positive (r=0.74) SARS-CoV-2 cases, between CRP and PCT in SARS-CoV-2 negative (r=0.38) and positive (r=0.44) cases, and between IL-6 and PCT in SARS-CoV-2 negative (r=0.37) and positive (r=0.40) cases. The area under the curve (AUC) of none of the biomarkers could efficiently discriminate patients with negative or positive swabs (CRP: 0.52; IL-6: 0.51; PCT: 0.53). Conclusions: routine measurement of CRP and IL-6, together with PCT, does not seem a useful pre-test strategy in ED patients with clinical suspicion of COVID-19.