Interleukin-8 and procalcitonin in early diagnosis of early severe bacterial infection in critically ill neonates.

We studied the value of serum interleukin-8 (IL-8) and procalcitonin (PCT) in the early diagnosis of early severe bacterial infection in 58 critically ill ventilated neonates. ELISA was used for determining IL-8 and immunoluminometric assay for PCT. IL-8 and PCT were compared with routinely used serum C-reactive protein (CRP). Neonates were divided into four groups: Ia--proven severe bacterial infection (n = 9), Ib--clinical sepsis (n = 16), II--respiratory distress without bacterial infection (n = 12), and III--various types of neonatal distress (n = 21). Sera were collected on admission, at 24 h and 48 h after admission. There was no significant difference between groups Ia and Ib for either parameter at any time interval. Significant difference was found between group Ia+b (septic neonates) and group II for PCT and CRP at 24 and 48 h, but not for IL-8. There was no difference between group Ia+b and group III except for CRP at 24 h. Diagnostic accuracy was best for PCT on admission and for CRP at 24 h. Serum PCT and IL-8 are not specific markers for early severe bacterial infection in critically ill neonates and are not better than CRP.