Clinical variables

Temperature instability Heart rate ≥180 beats/min or ≤100 beats/min Respiratory rate >60 breaths/min plus grunting or desaturations Lethargy/altered mental status Glucose intolerance (plasma glucose >10 mmol/l) Feed intolerance

Hemodynamic variables

Blood pressure 2 SD below normal for age Systolic pressure <50 mm Hg (newborn day 1) Systolic pressure <65 mm Hg (infants ≤ 1 month)

Tissue perfusion variables

Capillary refill >3 s Plasma lactate >3 mmol/l

Inflammatory variables

Leukocytosis (WBC count >34 000 × 109/l) Leukopenia (WBC count <5000 × 109/l) Immature neutrophils >10% Immature:Total neutrophil ratio >0.2 Thrombocytopenia <100 000 × 109/l CRP >10 mg/l or 2 SD above normal value Procalcitonin >8.1 mg/dl or 2 SD above normal value IL-6 or IL-8 >70 pg/ml 16S PCR positive

Interpretation

Proven Sepsis: A positive blood culture or PCR in the presence of clinical signs and symptoms of infection. For CoNS two positive blood cultures or one positive blood culture plus a positive CRP. Probable Sepsis: Presence of signs and symptoms of infection and at least two abnormal laboratory results when blood culture is negative. Possible Sepsis: Presence of clinical signs and symptoms of infection plus raised CRP or IL-6/IL-8 level when blood culture is negative.

^aSD: standard deviation, WBC: white blood cell, CRP: C-reactive protein, IL: interleukin, PCR: polymerase chain reaction, CoNS: Coagulase-negative Staphylococcus or Staphylococcus non-aureus.