The value of interleukin-6 (IL-6) within 6 hours after birth in the prompt diagnosis of early-onset neonatal sepsis

BACKGROUND: To investigate the value of interleukin-6 (IL-6) for neonates within 6 hours after birth in the prompt diagnosis of early-onset neonatal sepsis (EONS). METHODS: The clinical and laboratory data of 129 neonates in the neonatal intensive care unit (NICU) of our center from March 31, 2017, to February 29, 2020, were retrospectively analyzed. These patients were divided into two groups on their disease conditions: the EONS group (n=66) and the healthy control group (n=63). All enrolled patients were born in our hospital’s Obstetrics Department and were admitted to the NICU within 2 hours after birth. The first session of the blood test was conducted within 4–6 hours after birth for the measurements of IL-6, C-reactive protein (CRP1), serum amyloid A1 (SAA1), and serum immunoglobulin M (IgM). The second session of the blood test was performed 12–24 hours after birth for procalcitonin (PCT), CRP2, and SAA2. All the tests were completed in our clinical laboratory. The non-parametric test (Mann-Whitney U test) was used to compare all parameters between these two groups. The receiver operating characteristic (ROC) curves were drawn to compare the diagnostic sensitivities and specificities. The pairwise comparisons of the ROC curves were on the MedCalc18.2.1 software. A P value of <0.05 was considered statistically significant. RESULTS: Gender, birth weight, and gestational age were matched between the EONS group and the control group (all P>0.05). The differences of IL-6, CRP2, PCT, and SAA2 were statistically significant between these two groups (all P<0.05), while there was no significant difference in CRP1, SAA1, and IgM (all P>0.05). The area under the ROC curve (AUC) is 1 (95% CI: 0.918–1.000), 1 (95% CI: 0.918–1.000), 1 (95% CI: 0.918–1.000), and 0.977 (95% CI: 0.878–0.999), respectively, for IL-6, CRP2, PCT, and SAA2. Pairwise comparisons among four biomarkers showed the diagnostic specificity and sensitivity of IL-6 were not significantly different from those of CRP2, PCT, and SAA2 (all P>0.05). CONCLUSIONS: IL-6 is a quick and independent diagnostic biomarker for EONS, and its sensitivity and specificity are inferior to the conventional inflammation markers, including CRP, PCT, and SAA.