This study suggests a great potential of the combination of interleukin-6 (IL-6) and C-reactive protein (CRP) in routine rapid diagnosis of late-onset bloodstream infection (LOBSI) development. Antibiotic treatment could be discontinued early due to high negative predictive value of all tested markers.
Positive blood culture, clinical signs of infection, and onset more than 72 hours after birth defined LOBSI.
Relative to other markers (procalcitonin and CRP), IL-6 level was superior.
For the presence of LOBSI, IL-6 levels greater than 100 ng/L had a sensitivity of 94% and a specificity of 99%.
The optimal cutoff values of IL-6, CRP, and PCT showed negative predictive values of 99%, 95%, and 93%, respectively.
In 97.9% of cases, successful prediction of LOBSI was achieved with the logistic regression model of IL-6 > 100 ng/L or CRP > 10 mg/L.