PECARN Febrile Infant Decision Tool | Risk Stratification Calculator for SBI

📋 Clinical Application

Purpose: Identifies febrile infants at low risk for serious bacterial infections (SBI: UTI, bacteremia, bacterial meningitis)

Population: Well-appearing febrile infants ≤90 days with temperature ≥38.0°C (100.4°F)

Exclusions: Critically ill infants, premature babies, pre-existing conditions, indwelling devices, soft tissue infections

Step 1: Select Infant Age Group

⚠️ Important Clinical Considerations

Infants ≤28 days: Higher risk for HSV infection - maintain low threshold for HSV evaluation and empiric acyclovir

Positive urinalysis: For infants 29-60 days, LP decision should be guided by inflammatory markers, not UA alone

Procalcitonin availability: Not all facilities have rapid PCT assays - consider alternative approaches if unavailable

Clinical judgment: These tools support but do not replace clinical assessment and shared decision-making with families

📖 How to Use This PECARN Tool - Complete Guide

Step-by-Step Instructions:

Verify Patient Eligibility: Confirm the infant is ≤90 days old, well-appearing, and has fever ≥38.0°C (100.4°F). Exclude critically ill infants, premature babies, or those with chronic conditions.
Select Age Group: Click either "0-60 Days" or "61-90 Days" based on the infant's age. This determines which validated criteria set will be used.
Obtain Laboratory Results:
- For 0-60 days: You need urinalysis, ANC, and procalcitonin
- For 61-90 days: Choose Rule A (urinalysis + temperature) or Rule B (procalcitonin + ANC)
Enter Values: Input all laboratory values carefully. Pay attention to units (cells/µL for ANC, ng/mL for PCT, °C for temperature).
Calculate Risk: Click "Calculate Risk" to see if the infant meets low-risk criteria.
Interpret Results: Review the classification (low-risk vs. not low-risk) and clinical recommendations provided.
Clinical Decision: Use the result to guide, not dictate, management decisions in consultation with institutional protocols and family preferences.

Understanding the Results:

Low Risk Result: Indicates the infant has a very low probability (<1%) of serious bacterial infection. May consider outpatient management with close follow-up, though clinical judgment and family circumstances must be considered.

Not Low Risk Result: Does not meet all low-risk criteria. Typically requires full sepsis evaluation including lumbar puncture, empiric antibiotics, and hospital admission pending culture results.

✅ Advantages (PROS)

Evidence-based validation from large multicenter studies
High negative predictive value (99.5-99.6%)
Reduces unnecessary lumbar punctures and hospitalizations
Decreases antibiotic exposure in low-risk infants
Standardizes approach across providers and institutions
Age-specific criteria improve accuracy
Multiple assessment options (61-90 days)
Incorporates objective laboratory values

⚠️ Limitations (CONS)

Requires procalcitonin, not available at all facilities
Cannot replace clinical judgment and experience
Not validated for critically ill or high-risk infants
Small risk of missed infections (sensitivity 86-97.7%)
Does not detect HSV infections specifically
Requires reliable follow-up for outpatient management
May not apply to all populations or settings
Laboratory thresholds can be institution-dependent

Important Warnings:

This tool should NOT be used for:

Infants appearing critically ill or in shock
Premature infants (<37 weeks gestation) adjusted for prematurity
Infants with complex medical conditions or immunodeficiency
Presence of focal bacterial infections (cellulitis, osteomyelitis)
Infants with indwelling catheters or recent procedures

🔬 Complete Information About PECARN Tool

What is PECARN?

PECARN stands for Pediatric Emergency Care Applied Research Network, a federally funded research network of emergency medicine departments dedicated to improving pediatric emergency care through multicenter research studies.

Background and Development:

The PECARN Febrile Infant Decision Tool was developed to address the clinical challenge of identifying which febrile young infants have serious bacterial infections (SBI) requiring aggressive treatment versus those who can be safely managed with less invasive approaches.

Why This Tool Matters: Historically, nearly all febrile young infants underwent extensive testing including lumbar puncture and received empiric antibiotics with hospitalization. However, only 5-10% actually have serious bacterial infections. This tool helps identify the 90-95% who are at low risk, potentially avoiding unnecessary procedures.

What are Serious Bacterial Infections (SBI)?

The tool targets three main serious bacterial infections:

Urinary Tract Infection (UTI): Most common SBI in young infants
Bacteremia: Bacteria in the bloodstream
Bacterial Meningitis: Infection of the brain/spinal cord membranes (most serious)

Age-Specific Criteria:

For Infants 0-60 Days Old:

Low-risk criteria (ALL must be met):

Negative urinalysis (no leukocyte esterase, no nitrites, <5 WBC/HPF)
Absolute Neutrophil Count (ANC) ≤4,090 cells/µL
Procalcitonin ≤1.71 ng/mL

Performance: Sensitivity 97.7%, Specificity 60%, NPV 99.6%, Negative LR 0.04

For Infants 61-90 Days Old:

Two validated approaches:

Rule A (UA-based): Low-risk if BOTH:

Negative urinalysis
Maximum temperature ≤38.9°C (102°F)

Performance: Sensitivity 86%, NPV 99.5%

Rule B (PCT-based): Low-risk if BOTH:

Procalcitonin ≤0.24 ng/mL
Absolute Neutrophil Count ≤10,710 cells/µL

Key Laboratory Tests Explained:

1. Urinalysis (UA):

Screens for urinary tract infection
Leukocyte esterase: enzyme from white blood cells
Nitrites: produced by bacteria
WBC/HPF: white blood cells per high-power field

2. Absolute Neutrophil Count (ANC):

Measures a specific type of white blood cell (neutrophils)
Elevated in bacterial infections
Calculated from complete blood count (CBC) with differential

3. Procalcitonin (PCT):

Biomarker that rises specifically with bacterial infections
More specific than traditional markers like C-reactive protein (CRP)
Requires special laboratory assay (not universally available)
Different thresholds for different age groups

Clinical Implementation:

Low-Risk Infants - Potential Management:

Outpatient management may be appropriate with close follow-up
Lumbar puncture may not be necessary (shared decision-making)
Antibiotics may be deferred based on clinical judgment
Mandatory: reliable caregivers, close follow-up within 24 hours

Not Low-Risk Infants - Typical Management:

Full sepsis evaluation including blood, urine, and CSF cultures
Empiric intravenous antibiotics (e.g., ampicillin + gentamicin or cefotaxime)
Hospital admission for observation
Consider acyclovir for infants ≤28 days (HSV risk)

Special Considerations:

Herpes Simplex Virus (HSV): Infants ≤28 days are at highest risk. PECARN criteria do not detect HSV, so maintain high suspicion in this age group, especially with fever, irritability, seizures, or CSF pleocytosis.

Procalcitonin Availability: Not all hospitals have rapid PCT assays. Alternative approaches include the Rochester, Philadelphia, or Boston criteria, though these may be less accurate.

Cultural and Social Factors: Outpatient management requires reliable transportation, access to follow-up care, and caregivers who can recognize warning signs.

Evidence Base and Validation:

Primary Studies:

2019 JAMA Pediatrics: Derivation study for 0-60 day criteria (1,821 infants)
2025 Pediatrics: Validation of 61-90 day criteria from PECARN Registry
Multiple external validation studies across different populations

Limitations of Studies:

Predominantly conducted in well-resourced emergency departments
May not generalize to all populations or healthcare settings
Rare events (bacterial meningitis) have wide confidence intervals

Comparison with Other Criteria:

Older criteria sets include:

Rochester Criteria: Uses temperature, WBC, bands, UA, and stool studies
Philadelphia Criteria: Similar but includes CSF parameters
Boston Criteria: More conservative, older age cutoffs

PECARN criteria are considered more accurate due to procalcitonin inclusion and larger validation studies.

Future Directions:

Research continues on:

Role of rapid viral testing (influenza, RSV) to further refine risk
Incorporation of machine learning and AI prediction models
Economic analyses of implementation strategies
Long-term outcomes of low-risk infants managed as outpatients

Disclaimer:

This tool is for educational and clinical decision support purposes only. It does not replace clinical judgment, thorough patient assessment, or consultation with specialists when appropriate. Always follow your institutional guidelines and incorporate family preferences through shared decision-making. Individual patient circumstances may warrant different management approaches than suggested by the tool.

📚 Key References and Citations

Primary Derivation Study (0-60 days): Kuppermann N, Dayan PS, Levine DA, et al. A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections. JAMA Pediatr. 2019;173(4):342-351.

Validation Study (61-90 days): Pantell RH, Roberts KB, Adams WG, et al. Evaluation of Febrile Infants 90 Days or Younger With Risk for Serious Bacterial Infections. Pediatrics. 2021;148(2):e2021050052.

Recent Registry Data: PECARN Registry Working Group. Clinical Prediction Rules for Febrile Infants 61 to 90 Days of Age. Pediatrics. 2025;156(3):e2025071666.

Performance Metrics (0-60 days): Sensitivity 97.7%, Specificity 60%, NPV 99.6%, NLR 0.04

This tool is for clinical decision support only. Always incorporate clinical judgment, institutional guidelines, and shared decision-making with families.

PECARN Febrile Infant Decision Tool