TNF and necrotizing enterocolitis: Plasma, urine, and fecal levels of inflammatory mediators and molecules involved in immune response that have been evaluated as potential biomarkers for diagnosis and prediction of NEC include acute phase proteins (C-reactive protein, procalcitonin, serum amyloid-A [SAA], platelet activating factor, hepcidin), toll-like receptors, cytokines (IL-6, IL-8, TNF-α), and chemokines.