pecarn_rule_febrile_infant_29_60_days: PECARN Rule for Low-Risk Febrile Infants (29-60 Days)

In cliot: Clinical Indices and Outcomes Tools

PECARN Rule for Low-Risk Febrile Infants (29-60 Days)

Description

Applies the PECARN clinical prediction rule to identify febrile infants aged 29-60 days who are at very low risk for serious bacterial infections (SBI), including bacteremia, bacterial meningitis, and urinary tract infection. The rule uses three objective laboratory criteria.

Usage

pecarn_rule_febrile_infant_29_60_days(urinalysis_positive,
                                        absolute_neutrophil_count, procalcitonin)

Arguments

urinalysis_positive	Numeric (0 or 1). Is the urinalysis positive? Defined as positive leukocyte esterase, nitrite, or >5 WBC/hpf. (1 = Yes).
absolute_neutrophil_count	Numeric. The absolute neutrophil count (ANC) in cells/uL or /mm^3. (Low risk threshold: <= 4090).
procalcitonin	Numeric. Serum procalcitonin level in ng/mL. (Low risk threshold: <= 1.71).

Details

The rule identifies infants as **Low Risk** if:

• Urinalysis is negative

• Absolute Neutrophil Count (ANC) \le 4090 cells/\muL

• Serum Procalcitonin \le 1.71 ng/mL

In the derivation/validation study, the sensitivity for SBI was very high (approx. 97.7-99.8%), with a high negative predictive value. It is specifically validated for well-appearing infants 29-60 days old with fever.

Value

A list containing:

Risk_Classification	"Low Risk" or "Not Low Risk".
Recommendation	Clinical guidance regarding the need for further workup (e.g., LP) and admission.

References

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. doi:10.1001/jamapediatrics.2018.5501

Examples

# Example 1: Low Risk
# Neg UA, ANC 3000, PCT 0.2
pecarn_rule_febrile_infant_29_60_days(0, 3000, 0.2)

# Example 2: High Risk (Positive UA)
# Pos UA (1), ANC 3000, PCT 0.2
pecarn_rule_febrile_infant_29_60_days(1, 3000, 0.2)

# Example 3: High Risk (High PCT)
# Neg UA, ANC 3000, PCT 2.0
pecarn_rule_febrile_infant_29_60_days(0, 3000, 2.0)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.