LCN2 and Hyperbilirubinemia: In addition to standard biomarkers, several new biomarkers for acute appendicitis, such as hyponatremia, hyperfibrinogenemia, hyperbilirubinemia, pentraxin-3 (PTX-3), neutrophil gelatinase-associated lipocalin (NGAL), or interleukin-6 (IL-6), have recently been investigated.