PECARN Febrile Infant

Complete Journal Club Article
Kuppermann N. et al. "A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections.". JAMA Pediatrics. 2019. 173(4):342-351.
PubMed Full text

Clinical Question

Can a clinical prediction rule using laboratory data identify febrile infants <60 days who are at low risk for serious bacterial infection or SBI (UTI, Bacteremia, Bacterial Meningitis) and reduce unnecessary lumbar punctures, antibiotics, and hospitalization?


This clinical decision rule based on urinalysis, absolute neutrophil count (ANC), and procalcitonin has a sensitivity of 97.7%, specificity of 60%, NPV of 99.6% and negative likelihood ratio of 0.04.

Major Points

This rule was derived and validated in a multicenter PECARN study. They identified three laboratory criteria:

  1. Normal urinalysis
    • presence of leukocyte esterase, nitrite, >5 WBCs
  2. Absolute Neutrophil Count (ANC) ≤4090/µL
  3. Serum procalcitonin ≤1.71 ng/mL
    • If all these criteria are met, the infant is at low risk of having SBI.

Study Design

Prospective, observational study at 26 emergency departments between March 2011 and May 2013


  • N=1,821
  • Derivation group: 908
  • Validation group: 913

Patient Demographics

Inclusion Criteria

Febrile infants <60 days of age and had blood cultures obtained. Fever defined as rectal temp of ≥ 38°C in the ED, prior healthcare setting, or home within 24 hours.

Exclusion Criteria

Infants who were critically ill, had antibiotics in previous 48 hours, history of prematurity (≤26 weeks gestation), pre-existing medical conditions, indwelling devices or soft tissue infections.


ED physicians (including fellows) performed history and physical exam, Yale Observation Scale, clinical suspicion of SBI. Blood and urine testing was obtained. CSF was obtained based on clinician discretion.


Serious bacterial infection (defined as urinary tract infection, bacteremia, bacterial meningitis)

UTI definition

  • At least 1,000 cfu/mL for suprapubic aspiration samples
  • At least 50,000 cfu/mL for catharized samples
  • 10,000-50,000 cfu/mL for catharized samples associated with abnormal UA

Prediction Rule Characteristics

  • Normal urinalysis
  • Absolute Neutrophil Count (ANC)≤4090/µL
  • Serum procalcitonin ≤1.71 ng/mL

Criticisms & Further Discussion


Not all hospitals and emergency departments have access to procalcitonin testing. Additionally, procalcitonin results may not be available in a timely manner to help with decision-making.

Urinary Tract Infection Definition

This study used a lower threshold for determining UTI than the American Academy of Pediatric guidelines. The reason for this was because sometimes young infants have lower colonies of bacteria in urine but does make this prediction rule more conservative

Young and Old Babies

Most SBIs happened in the younger age group (≤28 days) compared to the older age group (>28 days). 13% vs 7.7%.


This study did not include viral testing. Infants ≤28 days may also be at risk for HSV which can have devastating consequences if missed. Be cautious in this age group.

Low Prevalence of Disease

There was only a small number of patients with bacteremia and bacterial meningitis. This may affect confidence in application of this rule.

External Validation

The PECARN team has presented results of an external validation of this clinical prediction rule at several conferences. This utilized rounded numbers:

  • Negative UA
  • ANC < 4000 /µL
  • Procalcitonin <0.5 ng/mL

They found similar results with sensitivity 97.6%, specificity 61.1%, NPV 99.6%, negative LR 0.04. Publication is still pending.

External Links


This study was supported in part by grant H34MCO8509 from Health Resources and Services Administration, Emergency Services for Children and by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (grant R01HD062477). This project was also supported in part by the Health Resources and Services Administration, Maternal and Child Health Bureau, Emergency Medical Services for ChildrenNetwork Development Demonstration Program under cooperative agreements U03MC00008, U03MC00001, U03MC00003, U03MC00006, U03MC00007, U03MC22684, and U03MC22685.