The following is a summary of “Biomarkers and their association with bacterial illnesses in hypothermic infants,” published in the February 2023 issue of Emergency Medicine by Holland, et al.

For a study, researchers sought to explain the relationship between biomarkers and serious bacterial infection (SBI; UTI, bacteremia, and/or bacterial meningitis) in hypothermic newborns presenting to the emergency department (ED).

From January 2015 to December 2019, they conducted cross-sectional research in four university pediatric emergency departments, covering newborns under 90 days old who presented with a rectal temperature of ≤ 36.4 °C. With the use of exploratory analyses assessing procalcitonin and band counts, we built receiver operating characteristic (ROC) curves to assess the precision of blood biomarkers for diagnosing SBI, including white blood cell count (WBC), absolute neutrophil count (ANC), and platelets.

SBI was discovered in 55 (6.5%) of the 850 included newborns (53.5% of whom were male; median age was 13 [IQR 5-58 days]). The area under the curve (AUC; 95% CI) for WBC in babies with SBI was 0.70 (0.61-0.78), with a sensitivity of 0.64 (0.50-0.74) and a specificity 0.77. (0.74–0.80). Sensitivity was 0.69 (0.55-0.81), specificity was 0.77, and the AUC for ANC was 0.77 (0.70-0.84). The sensitivity and specificity for platelets were 0.6 (0.52–0.67), with a sensitivity 0.73 (0.59–0.84) and a specificity 0.5 (0.46–0.53). The WBC and ANC had only mediocre accuracy in detecting babies with SBI who were hypothermic. ANC once more showed poor accuracy with an AUC of 0.70 (0.55–0.85) when examining the performance of these biomarkers for detecting invasive bacterial infection (IBI; bacteremia and/or bacterial meningitis).

Biomarkers often employed in an infection workup were typically ineffective at detecting SBI in babies with hypothermia. The findings from the cohort of hypothermic newborns were comparable to those from infants that are feverish, indicating that the bioresponse to infection was identical in both groups of infants. Further research was needed to enhance risk classification for babies with hypothermia and to better direct evaluation and care.

Reference: sciencedirect.com/science/article/pii/S0735675722007483