Procalcitonin as a Marker of Severe Bacterial Infection in Children in the Emergency Department

Abstract

Procalcitonin, the prohormone of calcitonin, is a relatively new and innovative marker of bacterial infection that has multiple potential applications in the pediatric emergency department. In healthy individuals, circulating levels of procalcitonin are generally very low (<0.05 ng/mL), but in the setting of severe bacterial infection and sepsis, levels can increase by hundreds to thousands of fold within 4 to 6 hours. Although the exact physiologic function of procalcitonin has not been determined, the consistent response and rapid rise of this protein in the setting of severe bacterial infection make procalcitonin a very useful biomarker for invasive bacterial disease. In Europe, serum procalcitonin measurements are frequently used in the diagnosis and the management of patients in a variety of clinical settings. To date, the use of procalcitonin has been limited in the United States, but this valuable biomarker has many potential applications in both the pediatric emergency department and the intensive care unit. The intent of this article is to review the history of procalcitonin, describe the kinetics of the molecule in response to bacterial infection, describe the laboratory methods available for measuring procalcitonin, examine the main causes of procalcitonin elevation, and evaluate the potential applications of procalcitonin measurements in pediatric patients.

Clinical values of the early detection of serum procalcitonin, C‑reactive protein and white blood cells for neonates with infectious diseases

“…WBC is one of the commonly seen inflammatory markers in clinics. In pathological state, WBC level can show a remarkable increase or decrease due to different immunoreactions states and pathogenic bacteria, both of which indicated systemic bacterial infection 11,12. CRP level is one of the frequently used indexes for the diagnosis of infection currently in China 13.…”

The Pathogenesis of Sepsis

“…One study (109) demonstrated that different biomarkers had varying ability to predict subsequent sepsis; IL-6 performed better than PCT, which performed better than CRP. However, another study (110) found no significant difference in the IL-6 plasma levels of postoperative patients who developed SIRS compared with those who did not, but it did find that the ratio of TNF to IL-10 was predictive.…”

Procalcitonin

“…For example, levels of PCT are increased in typical, but to a lesser extent, atypical, pneumonia 46. Infections associated with Gram-negative bacteria also cause a greater elevation in PCT levels compared with Gram-positive infections47 as do some viral or fungal infections 48…”