Statistical Validity of Interleukin-6 as a Biomarker for the Diagnosis of Early-Onset Neonatal Sepsis

Use of empirical antibiotics in neonates with risk factors of early-onset neonatal sepsis (EOS) is a common practice. A laboratory parameter is needed to help in the accurate diagnosis of EOS to avoid unnecessary use of antibiotics. The aim of this prospective observational cohort study was to compare the statistical validity of cord blood interleukin-6 (IL-6) with conventional sepsis screening as an early diagnostic marker for EOS. Eighty-seven neonates with antenatal risk factors for sepsis were followed up for 72 h for the development of EOS. Cord blood was collected for measurement of IL-6 concentrations. Blood culture and conventional sepsis screening (total leukocyte count, absolute neutrophil count, C-reactive protein and micro-erythrocyte sedimentation rate) were sent for analysis soon after delivery. The study group comprised of symptomatic neonates with positive blood culture (n = 36). An equal number of gestational-age matched asymptomatic neonates without risk factor of sepsis served as controls. Statistical validity of IL-6 was compared with sepsis screening parameters as the diagnostic marker for EOS. Gram negative organisms were the predominant cause of EOS. The most commonly isolated organism was Acinetobacter baumanii. The sensitivity and specificity of IL-6 with a cut-off value of 40.5 pg/mL and area under curve of 0.959 were 92.3 and 90.48%, respectively. In contrast, the sensitivity and specificity of different parameters of sepsis screening ranged from 37.5–68.75% and 47.95–57.35%, respectively. In conclusion, cord blood IL-6 can be used as a highly sensitive and specific early diagnostic marker of EOS at a cut-off concentration of 40.5 pg/mL.