Reliability of IL-6 Alone and in Combination for Diagnosis of Late Onset Sepsis: a Systematic Review

Diagnosis of neonatal sepsis is difficult as signs and symptoms are nonspecific. Interleukin-6 (IL-6) is a promising marker for neonatal sepsis. We aimed to test the accuracy of IL-6 in term and preterm infants after 72 hours of life (late-onset sepsis-LOS). We searched for IL-6 diagnostic accuracy studies between 1990 and 2020 using the PubMed database. Study selection was performed. The range of reported IL-6 sensitivities and specificities was 68% to 100% and 28% to 100%, respectively, the median values were 85.7% and 82% from 15 studies including 1306 infants. Subgroup analysis was performed. Sensitivity (87% vs 82%), but not specificity (both 86%), was better in preterm infants than in preterm and term infants. Early sample collection had the highest sensitivity (84%), but the lowest specificity (86%). To assess quality we used a STARD checklist adapted for septic neonates. Limitation of this review include the heterogeneous group of studies on the one side and the small number of studies on the other side that analyzed different combinations of biomarker. We concluded that IL-6 had a good performance especially in the preterm infant population and best results are achieved by measurements at the time of LOS suspicion.