Presence of a documented infection (eg clinical evidence of pneumonia, skin or soft tissue infection, purpura fulminans, urinary tract infection, abdominal infection) or a diagnostic positive blood culture (community or hospital acquired) within the last 72 hours and at least two of the following, one of which must be abnormal temperature or leucocyte count[3] core temperature of >38.5°C or <36°C; tachycardia (mean heart rate >2 SD above normal for age); mean respiratory rate > 2 SD above normal for age; leucocyte count elevated or depressed for age.