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Procalcitonin to Detect Suspected Bacterial Infections in the PICU
Iris M Mandell1, Sara Aghamohammadi, Timothy Deakers
11Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA. 2Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA.
Insights
Procalcitonin levels were higher in critically ill children with bacterial infections, but not reliable enough to guide antibiotic decisions. This biomarker showed fair predictive ability, limiting its clinical utility in pediatric intensive care units.
Area of Science:
- Pediatric critical care medicine
- Infectious disease diagnostics
- Biomarker research
Background:
- Nonspecific symptoms in critically ill children often prompt suspicion of bacterial infection.
- Empiric antibiotics are frequently initiated pending microbiology results.
- Identifying reliable biomarkers for bacterial infection is crucial.
Purpose of the Study:
- To evaluate procalcitonin as a biomarker for predicting bacterial infection in critically ill children.
- To assess the utility of single and serial procalcitonin measurements before culture results are available.
Main Methods:
- Prospective, blinded, single-center study in a pediatric and cardiothoracic intensive care unit.
- 144 children with suspected bacterial infections had procalcitonin levels measured at three time points.
- Outcomes were stratified based on microbiology and clinical criteria, blinded to procalcitonin levels.
Main Results:
- Procalcitonin levels were significantly higher in confirmed bacterial infections versus low suspicion (p < 0.02).
- High variability in procalcitonin values was observed across all groups.
- Procalcitonin demonstrated only fair predictive ability (AUC 0.63–0.71) for bacterial infection.
Conclusions:
- While procalcitonin levels were elevated in confirmed infections, they lacked sufficient certainty for clinical decision-making.
- Neither single nor serial procalcitonin measurements reliably predicted bacterial infection to guide antibiotic initiation or withholding.
- The clinical utility of procalcitonin for managing suspected bacterial infections in pediatric ICUs remains limited.
Objectives:
Nonspecific clinical symptoms frequently lead to suspicion of bacterial infection in critically ill children. Clinicians send bacterial cultures for suspected infection and begin an empiric course of antibiotics while microbiology results are pending. We investigated whether the biomarker procalcitonin could be useful to predict confirmed bacterial infection in critically ill children in the PICU, before culture results are available.
Design:
Prospective, blinded single-center study.
Setting:
Tertiary PICU and cardiothoracic ICU.
Patients:
There were one hundred forty-four patients with suspected bacterial infections that had bacterial cultures sent by clinicians.
Interventions:
Procalcitonin samples were obtained at three time intervals: as close to the time of the initial culture as possible (up to 12 hr after) and 24 and 72 hours after the initial culture. Patients were stratified into clinical outcome groups based on microbiology results and clinical symptoms using Centers for Disease Control and Prevention criteria. These assignments were blinded to procalcitonin levels. Primary outcome was the presence of culture-proven bacterial infection.
Measurements And Main Results:
There was a statistically significant difference in initial and subsequent median procalcitonin values between patients with confirmed bacterial infections and patients with low suspicion of bacterial infection (p < 0.02). However, there was extremely high variability in procalcitonin values among all groups. Procalcitonin had only a fair ability to predict bacterial infection, with area under the curve of receiver operating characteristic plots ranging between 0.63 and 0.71. When using serial procalcitonin values to predict bacterial infection, positive likelihood ratios were near 1 and negative likelihood ratios were between 0.3 and 0.4.
Conclusions:
Procalcitonin levels were higher in children with documented confirmed bacterial infection as compared with those with low suspicion of infection. However, neither single nor serial procalcitonin measurements were able to predict the presence or absence of confirmed bacterial infection with enough certainty to be clinically useful as to recommend initiating or withholding antibiotics.
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