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

Abstract

ObjectivesProcalcitonin (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.MethodsWe 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.ResultsThirty-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).ConclusionsProcalcitonin (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.

Evaluation of Procalcitonin's Utility to Predict Concomitant Bacterial Pneumonia in Critically Ill COVID-19 Patients

“…Previous studies have demonstrated that although PCT is not a reliable indicator of the presence of concomitant bacterial pneumonia in COVID-19 patients, its absence is assured with a negative predictive value (NPV) of 91.7% or higher. 13 , 14 This was not demonstrated in our critically ill population, where NPV was only 73.2%. Prior research in this area has not targeted ICU patients with COVID-19, likely accounting for the discrepant predictivity of PCT.…”

“… 6 , 7 , 9 , 21 , 29 Cutoff values of 0.1, 0.25, and 0.5 ng/mL have been used in high quality studies to assess the correlation between PCT and bacterial PNA. 5 , 14 , 22 …”

“… 11 Similar results were demonstrated by Dolci, et al They found that a PCT of greater than 6.7 ug/L had moderate strength in predicting in-hospital death, but did not add value as a diagnostic or prognostic biomarker compared to other more common markers of infection such as blood lymphocyte percentage and neutrophil count. 14 …”

“…Conflicting evidence exists regarding the utility of procalcitonin in diagnosing bacterial coinfections. 10 – 14 PCT has been investigated as a tool to diagnose ventilator-associated pneumonia (VAP) 15 and secondary pulmonary infections, including both viral and bacterial infections, in patients with COVID-19. 16 , 17 Although early literature suggests that elevated PCT is associated with COVID-19 disease severity and increased mortality, there is a paucity of data specific to critically ill COVID-19 patients with concomitant bacterial pneumonia.…”

Antimicrobial prescription in severe COVID-19 and CAP: a matched case-control study

“…A procalcitonin (PCT)guided algorithm could be used to trigger watchful waiting or aid in decreasing prolonged antimicrobial courses [28,29]. However, PCT-based strategies for outcome prognostication and prediction of ICU-acquired infections have not yet been adequately validated in COVID-19 [30,31].…”