[Usefulness of a rapid serum interleukin-6 test combined with C-reactive protein to predict sepsis in newborns with suspicion of infection].
OBJECTIVE
To evaluate the diagnostic value of interleukin-6 (IL-6) to predict the likelihood of neonatal sepsis in order to design an algorithm to decide antibiotic therapy.


METHODS
IL-6 and C-reactive protein (CRP) were determined in 42 newborns with clinical suspicion of infection. Newborns were classified as a confirmed, probable or no infection, based on the results of cultures, chest X-rays and the involvement of four or more clinical areas on a scale of eight. Samples for IL-6 were collected in the initial assessment and frozen until its determination at the end of the study. Blinded IL-6 measurements were performed using a rapid test. Receiver operator characteristics curves (ROC) for CRP and IL-6 versus infection (confirmed or probable) were determined.


RESULTS
Among the 42 cases included in the study 11 (26.2%) were classified as confirmed or probable infection. The area under curve (AUC) for IL-6 was 0.9, with a cut-off value of 53 pg/ml: sensitivity 90.91%, specificity 80%, positive predictive value (PPV) 62.5% and negative (NPV) 96% The level of IL-6>96 pg/ml and/or the combination of IL-6>53+CRP>13.3 mg/l, were the markers that best predicted infection: specificity 100% and PPV: 100%.


CONCLUSIONS
Assessment of IL-6 could allow withholding or early discontinuation of antibiotics in newborns with IL-6<54 pg/ml. In cases with IL-6>96 pg/ml and/or IL-6>53+ CRP>13.3, antibiotics should be started promptly, given the high likelihood of infection. Implementation of an algorithm based on the determination of IL-6 and CRP, in the initial assessment of the newborn with clinical suspicion of infection, could reduce unnecessary antibiotic therapy.
Beceiro Mosquera
J
J
Servicio de Pediatría, Hospital Universitario Príncipe de Asturias, Campus Universitario, Alcalá de Henares, Madrid, España. jbeceiro.hupa@salud.madrid.org
Sivera Monzo
C L
CL
Oria de Rueda Salguero
O
O
Olivas López de Soria
C
C
Herbozo Nory
C
C
D000465:Algorithms; D002097:C-Reactive Protein / Q000032:analysis*; D006403:Hematologic Tests; D006801:Humans; D007231:Infant, Newborn; D007239:Infections / Q000097:blood / Q000175:diagnosis; D015850:Interleukin-6 / Q000097:blood*; D011237:Predictive Value of Tests; D018805:Sepsis / Q000097:blood* / Q000175:diagnosis*; D013997:Time Factors
D015850:Interleukin-6; D002097:C-Reactive Protein