To test whether serum cytokines might be early biomarkers of AKI, we examined serum IL-1β, IL-5, IL-6, IL-8, IL-10, IL-17, IL-18, interferon (IFN)-γ, TNF-α, granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in pediatric patients with and without AKI, 2, 12, and 24 hours after cardiopulmonary bypass (CPB). Here, TNF is linked to acute kidney injury.