The role of sample collection timing on interleukin-6 levels in early-onset neonatal sepsis.
OBJECTIVE
To assess different perinatal findings and sample collection timing in newborns with early-onset sepsis comparing those with low IL-6 levels to the ones with high levels.


METHODS
Eighty-five newborn infants, with clinical signs of sepsis and/or positive blood cultures, had plasma IL-6 collected in the initial evaluation for early-onset sepsis in the first 96 hours of life. They were classified in two groups according to their plasma IL-6 levels: higher, and equal to or lower than IL-6 median value for the whole septic group.


RESULTS
Median IL-6 for the whole group was 89 pg/ml. High and low level groups were formed by 42 and 43 newborns respectively. There were no differences between the two groups regarding gestational ages, birth weights, cesarean-section proportion, Apgar scores, number of neonates with maternal risk factors for infection, number of maternal intrapartum antibiotic therapy, and number of positive blood cultures. Median plasma IL-6 in the high level group was 287 pg/ml, and in the low level group 46 pg/ml (p < 0.001). Median sample timing was 17.5 hours of life for the high level group and 36 hours of life for the low level group (p < 0.001). There was a significant negative correlation coefficient between IL-6 levels and sample collection timing.


CONCLUSIONS
Sample collection timing is an important factor for detection of high plasma IL-6 level in newborn infants with early-onset sepsis.
Procianoy
Renato S
RS
Universidade Federal do Rio Grande do Sul (UFRGS), Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil. renatosp@terra.com.br
Silveira
Rita C
RC
D015415:Biomarkers / Q000097:blood; D001800:Blood Specimen Collection; D006801:Humans; D007231:Infant, Newborn; D015850:Interleukin-6 / Q000097:blood*; D011446:Prospective Studies; D018805:Sepsis / Q000097:blood*; D013997:Time Factors
D015415:Biomarkers; D015850:Interleukin-6