Interleukin-6 as diagnostic marker for neonatal sepsis: determination of Access IL-6 cutoff for newborns.

Neonatal infections are by far the most common cause of childhood morbidity and mortality. To accelerate the diagnosis of a bacterial infection, IL-6 is increasingly used in neonatal diagnostics. The advantage is the level of IL-6 rises at the onset of infection while CRP reaches the maximum concentration with a noticeable delay. This analytical study was conducted to determine the Access IL-6 immunoassay normal range in neonates on postnatal day 1. A total of 124 serum samples from newborns were collected for IL-6 determination. Only those values were accepted for normal range calculation when the children's leukocyte count and CRP were not elevated and the newborns did not receive any antibiotic medication. The median was determined as 19.5 (SD = 14.7). The minimal and maximal IL-6 value was measured as 0.10 and 113 pg/mL, respectively. The upper value of the 95% reference interval was calculated as 44.4 pg/mL with a 90% confidence interval from 30.3 to 66.4 pg/mL. The cutoff determined can now be used to measure IL-6 as a prematurely pro-inflammatory marker in neonates.