BLOOD biomarkers, with the exception of procalcitonin, perform worse at identifying invasive bacterial infections in febrile infants with very short durations of fever, as demonstrated by research conducted by Roberto Velasco Zúñiga MD, PhD, assistant physician in paediatrics at Parc Taulí University Hospital in Sabadell, Spain, and colleagues. The reduced performance makes clinical decisions more difficult in a vulnerable age group.
Zúñiga and colleagues conducted a secondary analysis of a prospective single-centre registry at Cruces University Hospital in the paediatric emergency department between 2008-2021. The team analysed the effectiveness of blood biomarkers in febrile infants under 90 days old. The study categorised 2,411 infants into groups based on the duration of their fever: less than 2 hours, 2-12 hours, and 12 or more hours.
Among these infants, 3.0% were diagnosed with invasive bacterial infections, with 26.3% of the infants presenting with fevers lasting less than 2 hours. The researchers aimed to determine the reliability of several biomarkers (absolute neutrophil count, C-reactive protein, and procalcitonin) in accurately identifying bacterial infections in these different fever duration groups.
There was a significant decline in the performance of absolute neutrophil count and C-reactive protein in infants with fevers of less than 2 hours. Specifically, the area under the curve for absolute neutrophil count was 0.562 for fevers less than 2 hours, compared to 0.609 for fevers lasting between 2 and 12 hours, and 0.728 for fevers longer than 12 hours. Similarly, the area under the curve for C-reactive protein was 0.568, 0.760 and 0.812, respectively. In contrast, procalcitonin remained more consistent across groups (0.749, 0.780, and 0.773). Additionally, procalcitonin demonstrated perfect sensitivity (100%) in infants over 21 days old with negative urine dipstick results and less than 2 hours of fever, albeit with moderate specificity (53.8%).
“Unfortunately, we have found that, in effect, one in 10 patients with less than 2 hours of fever may have an invasive infection despite having normal biomarkers, but we have not been able to offer an alternative management,” Zúñiga explained.
Zúñiga and his colleagues are considering developing a large, multicentre study to identify the best management strategies. “Our impression is that possibly the use of procalcitonin, with cut-off points different from the usual ones, could be the ideal option,” Zúñiga said.
Reference
Velasco R et al. Performance of Febrile Infant Algorithms by Duration of Fever. Pediatrics. 2024;153(5):e2023064342.
