Validation of a laboratory risk index score for the identification of severe bacterial infection in children with fever without source.
OBJECTIVE
The identification of severe bacterial infection (SBI)in children with fever without source (FWS) remains a diagnostic problem. The authors previously developed in their Swiss population a risk index score, called the Lab-score, associating three independent predictors of SBI, namely C reactive protein (CRP), procalcitonin (PCT) and urinary dipstick. The objective of this study was to validate the Lab-score in a population of children with FWS different from the derivation model.


METHODS
A prospective study, conducted in Padova, on 408 children aged 7 days to 36 months with FWS was recently published. PCT, CRP, white blood cell count (WBC) and urinary dipstick were determined in all children. The Lab-score was applied to this population and the diagnostic characteristics for the detection of SBI were calculated for the Lab-score and for any single variable used in the Italian study.


RESULTS
For the identification of SBI, the sensitivity of a score ≥3 was 86% (95% CI 77% to 92%) and the specificity 83% (95% CI 79% to 87%). The area under the receiver operating characteristic curve for the Lab-score (0.91) was significantly superior to that of any single variable: 0.71 for WBC, 0.86 for CRP and 0.84 for PCT. The Lab-score performed better than other laboratory markers, even when applied to children of different age groups (<3 months, 3-12 months and >12 months). The results obtained in this validation set population were comparable with those of the derivation set population.


CONCLUSIONS
This study validated the Lab-score as a valuable tool to identify SBI in children with FWS.
Division of Pediatric Emergency Medicine, Geneva University Hospitals and University of Geneva, Geneva, Switzerland. annick.galetto@hcuge.ch
Annick
A
Galetto-Lacour
Samuel A
SA
Zamora
Barbara
B
Andreola
Silvia
S
Bressan
Laurence
L
Lacroix
Liviana
L
Da Dalt
Alain
A
Gervaix
D001424:Bacterial Infections / Q000150:complications / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D042241:Early Diagnosis; D004636:Emergency Service, Hospital; D004812:Epidemiologic Methods; D005260:Female; D005334:Fever / Q000382:microbiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007958:Leukocyte Count; D008297:Male; D011498:Protein Precursors / Q000097:blood; D011934:Reagent Strips; D016482:Urinalysis / Q000379:methods
D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D011934:Reagent Strips; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide