• ALT 2× upper limit of normal for age TABLE 10.3 RECOMMENDED LABORATORY TESTING IN SUSPECTED SEPSIS Source testing • Blood culture • Urinalysis, urine culture • Consider other cultures based on suspected source (e.g., lumbar puncture, drainage of abscess, or fluid collection) • CXR and other focused radiologic studies • Influenza and other viral testing • Consider procalcitonin, C-reactive protein as biomarkers for presence of infection Perfusion • Lactate • Base deficit • Central venous oxygen saturation (ScvO2 ) Respiratory Hematologi c Renal Hepatic • Blood gas if clinically indicated • Complete blood count • Coagulation studies (PTT, PT/INR, fibrinogen, d-dimer) • Serum creatinine • Transaminases (ALT, AST) • Bilirubin • Albumin There have been efforts to determine whether additional laboratory testing including white blood cell count, immature neutrophils, C-reactive protein (CRP), and procalcitonin may have predictive value for sepsis in children with compensated shock Increased procalcitonin has been associated with an increased likelihood of bacterial infection and septic shock While these biomarkers may suggest a patient is more likely to require treatment for bacterial sepsis, optimal thresholds and their clinical utility have yet to be demonstrated rigorously Increasing evidence shows that both venous and arterial lactate levels in the ED are associated with risk of organ dysfunction in pediatric sepsis and risk of death at the time of pediatric intensive care unit (PICU) admission While the optimal cutoff remains to be defined, lactate ≥2 mmol/L is worrisome and associated with worse outcome