Can Procalcitonin (PCT) be used in pediatric patients?

Use of Procalcitonin (PCT) in Pediatric Patients

Procalcitonin can be used in pediatric patients, but it cannot be used as the sole determinant to distinguish between viral and bacterial causes of community-acquired pneumonia. 1

Diagnostic Value in Pediatrics

Procalcitonin has demonstrated utility in pediatric patients across several clinical scenarios:

• Community-Acquired Pneumonia (CAP): The Pediatric Infectious Diseases Society and Infectious Diseases Society of America guidelines clearly state that PCT cannot be used alone to differentiate between viral and bacterial causes of CAP in children 1.

• Sepsis Management: In pediatric sepsis, PCT can be used to guide antibiotic therapy decisions. The Surviving Sepsis Campaign suggests using PCT to guide antibiotic discontinuation rather than initiation in children with sepsis-associated organ dysfunction 1.

• Appendicitis: In pediatric patients with suspected appendicitis, PCT has shown greater diagnostic value in identifying complicated appendicitis compared to simple appendicitis, with a pooled sensitivity of 0.89 and specificity of 0.90 1.

PCT Interpretation in Children

PCT levels should be interpreted differently in pediatric patients:

• Normal values: <0.05 ng/mL in healthy children 2
• Clinical interpretation:
  • <0.1 ng/mL: High probability of viral infection or non-infectious condition
  • 0.1-0.25 ng/mL: Low probability of bacterial infection
  • 0.25-0.5 ng/mL: Possible bacterial infection

  • 0.5 ng/mL: High probability of bacterial infection

  • 2.0 ng/mL: High probability of sepsis or severe bacterial infection 2

Specific Pediatric Applications

Febrile Infants

In well-appearing young infants (<3 months) with fever without source, PCT performs better than CRP in identifying patients with invasive bacterial infections (IBIs) with:

• PCT ≥0.5 ng/mL was the only independent risk factor for IBI in multivariate analysis
• Negative likelihood ratio for PCT <0.5 ng/mL was 0.25, making it valuable for ruling out IBIs 3

Respiratory Infections

In children <5 years with viral lower respiratory tract infections:

• A PCT threshold of 1.4 ng/mL has shown utility in determining bacterial coinfection with specificity of 83% and negative predictive value of 76% 4
• Serial PCT measurements may help influence correct treatment decisions in 44% of cases 4

Antibiotic Stewardship

The use of PCT in pediatric intensive care can guide antibiotic therapy:

• PCT-guided therapy can reduce antibiotic exposure in hospitalized children 2
• Serial measurements showing decreasing levels (≥80% from peak or to <0.25 ng/mL) can support safe antibiotic discontinuation 2

Limitations and Considerations

• Not a standalone test: PCT should always be interpreted in conjunction with clinical assessment 2
• Potential false elevations: PCT can be elevated during severe viral illnesses, including influenza 2
• Timing matters: PCT rises earlier (4 hours) than CRP (12-24 hours) after infection onset, allowing for earlier diagnosis 2
• Serial measurements: Trends in PCT levels are more valuable than single measurements 2

Clinical Algorithm for PCT Use in Pediatrics

1. Initial assessment: Perform clinical evaluation and obtain appropriate cultures before starting antibiotics
2. Measure baseline PCT: Consider in conjunction with other inflammatory markers (WBC, CRP)
3. Interpret based on clinical context:
   • In suspected sepsis: Do not delay antibiotics regardless of PCT level
   • In CAP: Do not use PCT alone to determine bacterial vs. viral etiology
   • In febrile infants: Consider PCT <0.5 ng/mL as supportive evidence against IBI
4. Serial monitoring: Repeat PCT every 48-72 hours after day 3 to guide antibiotic duration 1
5. Consider discontinuation: When PCT decreases by ≥80% from peak or to <0.25 ng/mL 1

By following this approach, PCT can be a valuable tool in pediatric patients, particularly for guiding antibiotic duration and helping to rule out serious bacterial infections when levels are low.