Searching for a role of procalcitonin determination in COVID-19: A study on a selected cohort of hospitalized patients

Procalcitonin (PCT) has been proposed for differentiating viral vs bacterial infections In COVID-19, some preliminary results have shown that PCT testing could act as a predictor of bacterial co-infection and be a useful marker for assessment of disease severity We studied 83 COVID-19 hospitalized patients in whom PCT was specifically ordered by attending physicians PCT results were evaluated according to the ability to accurately predict bacterial co-infections and death in comparison with other known biomarkers of infection and with major laboratory predictors of COVID-19 severity Thirty-three (39 8%) patients suffered an in-hospital bacterial co-infection and 44 (53 0%) patients died In predicting bacterial co-infection, PCT showed a relatively low accuracy (area under receiver-operating characteristic [ROC] curve [AUC]: 0 757;95% confidence interval [CI]: 0 651-0 845), with a strength for detecting the outcome not significantly different from that of white blood cell count and C-reactive protein (CRP) In predicting patient death, PCT showed an AUC of 0 815 (CI: 0 714-0 892), not better than those of other more common laboratory tests, such as blood lymphocyte percentage (AUC: 0 874, p=0 19), serum lactate dehydrogenase (AUC: 0 860, p=0 47), blood neutrophil count (AUC: 0 845, p=0 59), and serum albumin (AUC: 0 839, p=0 73) Procalcitonin (PCT) testing, even when appropriately ordered, did not provide a significant added value in COVID-19 patients when compared with more consolidated biomarkers of infection and poor clinical outcome The major application of PCT in COVID-19 is its ability, associated with a negative predictive value >90%, to exclude a bacterial co-infection when a rule-out cut-off (<0 25 μg/L) is applied © 2020 Walter de Gruyter GmbH, Berlin/Boston